I use uYou plus. It has to be installed via Altstore (which means you have to resign it once a week with a computer needed in the same network).

But it has the best features:

• Adblock
• Sponsorblock (automatically skips sponsor segments in videos)
• allows pip playback
• shows estimated dislikes again

I have been using Orion Browser (by Kagi) for the last couple of weeks and haven’t seen a single ad on YouTube since.

Safari + AdGuard + PiPifier would probably be a good combo.

I use a private safari window with Vinegar

Look up Vinegar for iOS and install

Been using it for some years now

I use the following with mobile version of YouTube in safari (not desktop version) on iPad 9.

Wiper adblock $1.99 one time payment (no subscription).

https://apps.apple.com/us/app/wipr/id1030595027

SponsorBlock $1.99 one time payment (no subscription).

https://apps.apple.com/us/app/sponsorblock-for-safari/id1573461917

If you want a standalone app and not a safari workaround, I recommend video lite. Works for twitch too.