I was previously considering to make my next phone an iPhone (better integration with my MacBook), but I recently discovered Youtube Vanced and realized that if I'm ever going to watch non-trivial amounts of Youtube on my phone it might be worth it to stay on Android just for that app.

Both Vanced and NewPipe are pretty good YT alternatives.

Vanced is a modded YT app, while NewPipe is open source and has a background player too, with download feature.

You can use a DNS based solution on iOS. It's easy for WiFi and there are apps that can change it for the cellular network as well.

I have run a pihole at home for a while now. YouTube ads still show.

They increasingly use the same servers for ads, so a DNS-based solution won't work well.

You don't need a DNS based solution, you can just use the "AdGuard" app, which will block ads in Safari.

However, neither Adguard nor DNS based blocking will block ads in the iOS Youtube App.

Pythonista on iOS can run yt-dl, works well