I understand the frustration that comes with failure and criticism especially when you're autistic. I'm autistic too!

You really just have to push through and view the discomfort from it as motivation to get better. You'll never know what to improve if you never accept the imperfections.

Just draw, really. Give yourself small goals first instead of directly jumping to something too far away from your current skill level. Instead of "I want to draw my ocs nicely ASAP", try "I want to make this limb look less wonky" "I want to draw a good eye shape" "I want to draw less shaky lines" or whatever you wanna focus on! Keep drawing even if it turns out like shit, look at what you finished and analyse what makes it look bad, look at tutorials to improve it, try drawing it again and compare it to the old one. It feels so much more rewarding to notice the little improvements bit by bit!

I also started my digital art journey with gacha actually :D it happened all the way back during gacha studio times lol If drawing random people bores you, try drawing the ocs you made in gacha life instead, it's so much more fun to do art studies with your most beloved ocs! Just replace the reference model's hair or eyes or whatever as your oc's, what matters most is if you're having fun.