How to deal with Autism and ADHD when drawing?

Hey everyone, this is my first post here, but I'm writing because I need advice from someone who struggles with the same problem as someone with autism spectrum disorder (AUDHD). Before I can explain the situation, I'd first like to share my experience.

About eight months ago, I learned that I'm autistic with ADHD. I'd never been diagnosed with it before, and my family thought my behavior stemmed from my autism, rather than from having both. I have both autism and ADHD. I'm not currently attending any therapy because I'm waiting for it to be available in my area, which is difficult to find. I have a very distressing problem that I can't cope with anymore, so I need advice.

Learning about what's going on inside me has opened my eyes to the problems I'm having with my hobby, drawing, which I've been pursuing since childhood. It causes me a lot of sadness, frustration, and a sense of giving up. For as long as I can remember, I've had trouble finishing projects I desperately want to finish. On the one hand, my brain tells me to finish them, and then I feel bored, as if ADHD saying: ''It's booooring, can we start something new?''. However, when I start a new project, I feel angry and sad because I can't finish what I started when others seem to manage it so easily. Maybe it means my drawings aren't good because I never finish them i always think like that. This has really demotivated me from doing this, or anything else that's my hobby—photography, clay modeling, video editing—because I feel overwhelmed because my mind is constantly fighting over what I should be doing...

I'm looking for advice from someone who has been or is in the same situation. How can I reduce this so it's not so burdensome? So I can enjoy what I love again?