Regarding sites serving ads from their own domains, YouTube and Twitch are the biggest offenders. Pihole won’t block their ads at all.
Problem with Raspberry Pi reliability is the storage. SDcards aren’t meant for continuous use, and they fail with depressing regularity. You can avoid that by using an external USB SSD, but the USB ports are only USB2 so that isn’t a fantastic solution either.
I run pihole in a linux container myself, works great. They have docker containers also.