What hack for me was stop thinking of it as "complete A or finish B". Instead I see it small pieces. "lets just hack this script on SO that will let me wrangle an API". "hey lets build an endpoint that will just take care of authentication"

doing this way I am not working on a dozen things trying to be perfect. rather each work feels just like a coding exercise.

having said that even getting into this mode is a challenge. you get carried away. you make love with your side project. you get attached.