First off, congrats on a new job that you're happy about! I think a change of pace could prove to be a really great motivator, and might help you see your comic in a different light. Also, it's absolutely possible to do a comic and work a full-time job-- some people work TWO jobs and do comics, some people work two jobs+make a comic+have a family to take care of. It's absolutely do-able, if you want to.
If doing regular comic updates alongside your day job doesn't sound like fun, there's no shame in doing it only when you feel like it. People assign way too much inferiority to hobbies, but really some things are better left as fun side projects. I do lots of creative stuff on the side just for fun, doesn't mean I'm bad at them.
Regarding critique, there's never gonna be a point where you're not gonna have things to fix. I agree that it's iffy when people offer critique you didn't ask for, but think of it this way: if your subs are critiquing you, it's because they like your work and want to see it get better. So while it might be a little frustrating, it comes with good intentions. I've had readers point out errors before, and my first reaction is usually "Ugh, stupid Michelle", but I also think "Huh, someone cared enough to point out a mistake cause they want my comic to look good!"
If you're really bent on improving, I would suggest you welcome those critiques in your description. Something like "Hey, I'm trying to improve my art so any thoughtful critiques are appreciated!" might change how you perceive people giving their 2 cents.
As for people messaging you basically shouting "HEY STOP MAKING COMICS", they're not worth the time it takes to read the message. :u That's not to say you should ignore critiques that point out a lot of flaws, but knowing how to differentiate critiques from outright jackassery is important.
I don't know how long you've been doing comics specifically, but if you've been working on LoA from 2015-2017... that's still not a huge amount of time in the grand scheme of things. I started publishing Centralia around the same time, but I had done other comics for years before then. Aaand... they weren't very good. It may be that LoA is a stepping-stone to something more solid down the line, but demanding that this one project be perfect will only lead to frustration.
If doing artwork is more frustration than joy, and you can't see yourself wanting to buckle down and learn the craft, it's ok to hire out an artist. Drawing IS frustrating, it's TOTALLY an uphill battle, and you're gonna be making drawing mistakes until you die. At the end of the day, I'd still rather draw because I hate writing. :u If writing is an easier form of communication for you, embrace that! It might be that a comic like LoA will thrive much better when working as a team. Not to mention, if your job takes a lot of your time, divvying up the workload makes sense.