I found that making lots of smaller projects and doing commercial work made me stop thinking in terms like "THIS is my comic! This is my one shot at greatness and if it isn't good what can I possibly do!?" turns out... life is kinda long and if you're regularly making content you can make a LOT of it.
I've making stuff of publishable quality since I was maybe 22-23 years old, and in that time I've worked on... I think 12 published games, I've lost count of how many comics and books, I think five or six with ISBNs and a host more small press ones... After doing all that I've kind of stopped feeling like "oh god, this needs to be perfect" and it's more like "all right, we know the drill at this point. Let's do this. Do the best I can do in the allotted time frame, learn from mistakes."
I have too many friends who have agonised over making one perfect project and then it's just got stuck and gone stagnant and they never went anywhere, and they tend not to end up completing any works or becoming pros. The ones who throw themselves in and just start making things, even though the things are imperfect and they may look back on them ten years later like "oh god that's so bad hahaha!" they tend to end up making higher quality work, more of it and to go places.
Do I finish a page of Errant and go "Well, that's PERFECT." No. Not in the slightest, a lot of the time it's like "hmm, that hand could be better, egh I didn't really nail that expression how I wanted, blegh that background is sloppy." but I always remind myself: The person who reads this, especially when they're binging the archive or reading in print, will probably only look at this art for like a minute tops. Also find looking at the quality level of premium and print comics helps, because there are so many mistakes and rough bits and shortcuts. Like have you seen how many of the top comics on tapas just plonk a 3D model in the background without any sort of painting over or editing? Have you seen how low-detail the art is in Invincible? Pros are always on a tight deadline and they only get so much money per page. It just isn't viable to do like one really amazing page and to go "look at me! I did a perfect page!" because to tell that story, you're gonna need a lot more than one... but on the upside, you'll find that so long as it's polished and readable... readers don't care. Like so long as it looks "pretty decent" and they're hooked on the story, they are perfectly happy!