YouTube ReVanced gets you completely adfree, configurably de-shittified Youtube with sponsorblock on your phone. (And Youtube Music ReVanced is premium YT music, for free, of course also without ads.)
And Smarttube Next does the same thing on Android TVs, FireTV, and probably some others I haven’t used.
Regarding 2: I don’t think I’ve ever seen this, in what situation would you rather share a video then a description of the problem + your log files?
Regarding 3: Should be fine as along as the script itself isn’t harmful. Which you can really only answer by reading the script. (And funnily enough, you’d find an answer to your first question inside this specific script…).
Do you seriously think advertisers buy each user’s data individually, and sometimes Google goes “oh hey guys just a heads up, that individual is using an ad blocker 👍🏼”?