I use DuckDuckGo for search, and it gives you the option to watch full YT videos without actually going to YouTube. I only watch videos that I’ve searched for - not ones that YT suggests to me, so this has been sufficient. Watching this way does not have ads (so far) but it does warn that YT can still use trackers.

Other’s advice (plugins etc.) are probably better overall, but this is the simplest option for me. I haven’t felt the need to find a more robust solution, but that’s only because of how I use YouTube.

Edit - when you click a DDG search result that is YT, this pops up:

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

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

I use a private safari window with Vinegar

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

Look up Vinegar for iOS and install

Been using it for some years now

If you use a VPN you can simply set your location to Albania and won't receive any ads on YT, as Google's ad platform doesn't support the Albanian language yet.

If you're cool with Invidious you can use instances via the Yattee app. (Not sure if it's available in every territory though.)

https://github.com/yattee/yattee

https://apps.apple.com/us/app/yattee/id1595136629

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

Late to the party but try Unwatched: RSS Video Player It’s blocking adds, has pip, no account needed, can disable shorts and so on. It’s basically premium on roids

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