That is not ideal, especially if you will be the only one using it. If you are using it alone, YouTube will still be able to profile you, as all the videos will be watched by a single server. It would be just like using YouTube.com with a VPN. If you are self-hosting and a few people will use it, YouTube won’t be able to profile everyone, as it will think all the videos are being watched by a single person.
The f-droid team goes through the source code and builds the app themselves before publishing. I think it’s better to trust them. Obtanium is great, but only if the app is not on f-droid or f-droid is lagging behind updates.