Sorry If It was seen that way, I guess I try to imagine how a social handle is seen both on social media where it really doesn't matter much and also If your own comic book is printed, how you were gonna name it as well or something.
For example Loish sounds nice because it even seems like a name. I guess that's the perspective lol
As you say, there are really no rules on social media" In fact I loved your nickname XD
I mostly use my real name for my art, though I do play around with my initials JRK (pronounced "jerk") and have that for my blog titles (jrked up art/jrking around) and instagram name (jrkingart). Though I avoid using it too much since I don't want people to think I'm a jerk.
For my gamer tag, right now I use TheKwandry for all my gaming accounts. I like it because 1. it's gender neutral 2. it's a pun on my last name and 3. it's not tied to some aspect that I might grow out of eventually.
I'll expound on the last point. When I was younger and on sites such as neopets, gaia, and deviantart, I played with a bunch of different usernames. I had multiple on neopets since I had more than one account. One of them was "petitewyvern" but now I've literally outgrown it. I'm not petite in stature and I'm not as into dragons as I once was. I have a few other usernames from back in the day, but I only use them for personal accounts out of nostalgia.
I would say that you want a username or handle to be something people can easily recognize as you and is easy to remember if they want to search for you. Mine happens to be my last name, but something like @KoreanTacos is easy to remember and I can easily associate that handle with their profile. @mgart1937 in the form its currently in is just a bunch of letters and numbers to me. MG_art_stories seems a little bit better in this regard. 
Just something to think about.
EDIT: My handle on the forums is a bit of a mystery to me as Tapas automatically made it match my email address that I use to log in. I didn't get a chance to actually choose a username. But everywhere else, facebook, twitter, etc. It's LadyArrowsmith.
How about just MGComics? I'd find that easier to remember than your current one, and it contains all the relevant info. Easy to read, easy to write.
ScampiCub has been a handle of mine for about 13 years now since the cringey deviantArt days. I kept it purely out of habit (and because my little sister liked it) but it has no meaning at all. it's easy to remember and I suppose that's all that matters. For anything important (business related, like Patreon of Ko-Fi) I use my real name. Most people online know me as Kate.
Slinger would make a fine username but it's ALWAYS taken. KJSlinger is fine too, but by now ScampiCub has stuck so, wevs.
I agree, though, some nicknames sound a bit unprofessional. Then again, 99% of people in and outside the industry understand we need to go with a more unusual tag sometimes, especially if your name is common. I see plenty of professionals with jokey nicknames. Just avoid anything outrageous and offensive and it won't be a big deal.
I'm not too sure if you're saying "The False Vyper" is unprofessional or my old one was lol
Either way, I know I chose to change my name because the old one was a random nickname my friends gave me when we were 15-16, and as I'm starting to take my artwork more seriously, I realized that I wanted to have a name that was easy to remember, and "better fitting" with the tone of my content.
I also knew that I needed to finalize it soon because I want my name to become recognizable! Changing it over and over again loses its value.
Pro Tip: I legitimately found a random adjective generator online and came up with the word "False". I just stuck that bad boy in front of my gamer tag name to create "The False Vyper".
Oh no!! As you could see, me telling you thank you for made me realize that a nickename, username is important and me talking about my nickname being unprofessional is not even in the same sentence 
What I meant is that since you posted deciding about your username, you made me think about changing mine. That's why I said it!
I actually liked yours, as I said in a previous post that you posted lol sorry for my english
Tbh I didn't redact well that I was imagining both a handle in social media and publishing a comic book at the same time. And felt me being kinda like publishing a serious book or something by "mg_art17" having the numbers and like a social media handle didn't fit. Sorry for making you all misunderstand that!
Thank you for the suggestion!
I like ScampiCub, it has a nice ring to it 
As you say! It's easy to remember <3 I think that's the most important thing, me having a number was against that , because people remember numbers is annoying for them.
Love the name Kate, many stories I have created have your name XD
Tbh I didn't redact well that I was imagining both a handle in social media and publishing a comic book at the same time. And felt me being kinda like publishing a serious book or something by "mg_art17" having the numbers and like a social media handle didn't fit. Sorry for making you all misunderstand that!
Loved your feedback, really thanks!
Yep! mg_art is much better, but should find something else.
Yep in the forum it's automatic! Like the part before the @ (It's actually very simple to code that, probably that's why Tapas did it)
Thank you for your feedback!
KoreanTacos is super good XD
That I think it's the best thing! Because If one day you publish a comic book or something people on social media know who you are as well!
To publish a comic book by "mg_art17" doesn't sound professional, though.. I will explain!
Tbh I didn't redact well that I was imagining both a handle in social media and publishing a comic book at the same time. And felt me being kinda like publishing a serious book or something by "mg_art17" having the numbers and like a social media handle didn't fit. Sorry for making you all misunderstand that!
Lol it's all good! I was only teasing anyway 
One thing you can consider doing is capitalizing and putting a period between your initials - M.G.
I think it looks professional and you can add other words to it more easily and it'll still make your name look clear and easy to remember.
For example: M.G. the Artist, or M.G. Comics
Those are just some suggestions, take from it what you will! I hope it helps
Thank you so much! Think it's brilliant the idea that you don't give off who you are by your name so people don't put weird expectations in you.
Like many guys don't like stories written by girls because they may think it will be cute or about love... And girls when they also put weird expectations on stories written by guys all about only action or things they don't like...
Tbh I didn't redact well that I was imagining both a handle in social media and publishing a comic book at the same time. And felt me being kinda like publishing a serious book or something by "mg_art17" having the numbers and like a social media handle didn't fit. Sorry for making you all misunderstand that!
Yep, that sucks! When you want to use a name that's taken... but it's yours!!
Really thank you for your feedback!!
Tbh I didn't redact well that I was imagining both a handle in social media and publishing a comic book at the same time. And felt me being kinda like publishing a serious book or something by "mg_art17" having the numbers and like a social media handle didn't fit. Sorry for making you all misunderstand that!
Yep, sweedish names are usually hard, right?
Idk, seems complicated names can be made a sort of acronym
Thank you for the idea! specially "about me" page, it's quite useful
Tbh I didn't redact well that I was imagining both a handle in social media and publishing a comic book at the same time. And felt me being kinda like publishing a serious book or something by "mg_art17" having the numbers and like a social media handle didn't fit. Sorry for making you all misunderstand that!
Yeah, the underscore and numbers do make it questionable if you're trying for a normal publication.
Maybe you can look into words that have MG in them and try to spin it off that?
Like:
MeGa
MoGwai
MissinG
MaGnesium
MaGpie
But PaulsTower is actually awesome! Seems like your real name, actually :')
I think that's a good idea, using pseudonyms (sorry for english, Idk how to put it)
Oh! Because of the "ero" part? And the 69 I guess lol!
I can imagine! Though I like your username mmm
I guess If you have a super big following you have more problems 
I don't know! That's why I was struggling as well and asked in this post XD Also feel like even names from famours people like "CutiePieMarzia" everyone know she's Marzia, or things like that. I think even her book bears her name as "...known as CutiePie" and stuff like that
