Is there a reason it needs to be an app? I was in a similar situation and what worked best for me was just replacing the YouTube app with a Firefox shortcut to YouTube.com. I’m still logged in and the uBlock Origin extension strips the ads out. I think the Sponsorblock extension should also work with this system.
In general I’ve just started replacing apps with annoying ads with either a Firefox webapp or a Firefox shortcut. Works great and reduces the app count on my phone too.