I had the same experience using the native Youtube app on iOS.
In my browsers (including on mobile), I always have adblock enabled but playing the video in the native Youtube app crams so many ads into a video it's ridiculous. They deliver ads on videos as short as 2 minutes long. Move onto the next video after watching an ad + 2 minute video == another ad.
I've stopped using the native app and have now switched to the mobile-browser version now (I use Adguard as an ad-blocker for mobile Safari which blocks YT ads in browser)..
In the last year (or so?) the amount of ads I see when using the iOS/tvOS YouTube native apps has steadily increased, where now I basically have to sit through 2 x 15s ads at the start of almost any video I want to watch.
And only after the second or third video I watch am I finally given the "skip" button, and then after a few more videos, it's back to unskippable for a while, etc..
Not to mention the constant push for YT Premium, it's every 3rd or 4th time I launch the app now that I have to tap past a full-screen interstitial asking me to subscribe.
Google is already steadily increasing the amount of ads they are making people sit through on YouTube, and so a move like this just feels like more steps down the same path they've already been on for quite a while.
Even if you don't pay for Premium, just using a VPN in a smaller country helps a lot. Make sure you have all the personalized ads turned off in privacy settings.
In my browsers (including on mobile), I always have adblock enabled but playing the video in the native Youtube app crams so many ads into a video it's ridiculous. They deliver ads on videos as short as 2 minutes long. Move onto the next video after watching an ad + 2 minute video == another ad.
I've stopped using the native app and have now switched to the mobile-browser version now (I use Adguard as an ad-blocker for mobile Safari which blocks YT ads in browser)..