Helló!
This is my Pi-hole Blocklist regex filter:
^r[0-9]{1,99}-*sn-*[a-z0-9]{1,99}-[a-z0-9]{1,99}\.googlevideo\.com$
This is very good filter.
Filters out all Youtube ads except 8 characters, such as:
rx.sn-xxxxxxxx.googlevideo.com
I realized that these should not be blocked. If they are blocked, the video will not start.
My filter blocks all but these ads.
Have a nice day.