So... People are saying apple tv, but if you hate ads, and also watch YouTube, then this is not the way. If you go with something androidTV based, you can side load smarttube plus, which not only will block ads without YouTube premium, but it also has sponsor block built in, which will skip sponsored sections in videos.
I use a nvidia shield since it supports the widest range of direct play standards (h265, Dolby atmos, hdr10 / Dolby vision, support for refresh rate and output resolution switching, so on)
There's tons of other androidTV based boxes to go with, but thats what my research ~3 years ago brought me to get, and ive been pretty happy with them. The only con is that it doesn't like Ethernet cables that dont have a metal shielding on the rj45 connector. Not sure why, but yeah
I run my own CA for internal SSL (think like homeassistant, nextcloud, so on)... Some of these apps dont respect the user CA store, so I have to load my internal CA cert into the system cert store.
I also use it for app backups, as well as spoofing google play services (I run stock lineageOS and added my own microG instead of using something like "microG for lineageos" which has it all pre bundled)
Ad blocking is another reason to do it... But I just use firefox, which can do adblocking at a user space level... And like 90% of my apps are foss, which dont have ads, so I dont personally use it for that