My current practical requirements: Lately, I mostly watch movies and series from borrowed Blu-ray and DVD discs (which turned out to be a better catalog, IMHO, than Netflix's streaming catalog at the time I switched). I also want to occasionally play PS4 online multiplayer games on the same display.
I didn't want the PS4 to be phoning home when I played the discs, so I found a model of Blu-ray player that does DVD 1080p upscaling, but which still doesn't have WiFi. I did a final firmware update of the (EOL'd) Blu-ray player over the Internet, and then have a policy that the player will never be plugged into the Internet again. (Again, this is mostly an on-principle exercise, and, so far, it's proven practical for me. I've encountered only one Blu-ray implementation bug, which is known lockups of a very small number of titles in 24p mode of some players, and which never got a firmware update anyway.)
(Before the Blu-ray player appliance, I tried using Kodi for playing DVDs, first with a laptop, and then a RasPi 3 setup, but that worked poorly.)
I paired the airgapped Blu-ray player with a nice older Sony 1080p TV with decent integrated speakers, and which had no WiFi, and was not new enough to be fully "smart TV" obnoxious. It has a nice picture, and works well with the Blu-ray player's remote over HDMI. To get this one, I had to do some research, and then do daily searches on CraigsList for a while.
The two main drawbacks to the older, less-smart TV are that it's not 4K, and that it's power-hungry. (20W off, 90W to display no-signal screen, peaks to 140W+ even in a dim room.) For saving the 20W when off, I'll probably move the TV to a secondary position on a smart power switch, but I've hesitated, because I don't know whether the TV was designed for frequent abrupt power cuts, and, if I wear it out prematurely, finding a similar replacement model on the used market looks increasingly difficult.
When I eventually upgrade to 4K or whatever is next, I suspect I'll probably end up getting a non-TV commercial display without Internet, and a separate audio amp and speakers.
Maybe I'll also be forced to give up on borrowed discs, and switch more to streaming, which I suspect will be locked-down with anti-user hardware and software, and (unless regulation really steps up) fraught with excessive corporate surveillance and other misbehavior (and possible attendant vulnerabilities, due to the complexity and methods).
There are some open source media player things I'd like to build, if I can ever spare the time again, but those might be precluded by the available (legal) consumer-hostile media methods at the time.