The best way to avoid adverts on YouTube on devices where you can't install uBlock origin is to go for YouTube Premium - I use
Gamsgo
I've tried PiHole's and various DNS services and from all my testing, they did not block adverts. The only consistent solution I've found was uBlock origin, but I don't know how reliable this is now, as I've been using YouTube Premium for over a year.
YouTube (Google) are not daft and they are imbedding adverts into the content now. Twitch do this so that browser extensions can't block the adverts. The adverts are coming from the same source as the content, so blocking adverts would also be blocking the content.