Blast from the past - stand alone DVD movie player
If you have (old) DVDs/CDs (or Blue Rays) with movies then all those modern TVs won't be able to play them without a separate player. Using a PC with a DVD reader is an option, but it can be an overkill when your TV is away from any PC to do that...
In short - there are simple stand-alone DVD players that can be used for movie discs. One of them is the one I got from Aliexpress. It comes with an RCA or HDMI connection option, and a remote, and can be powered via USB cable.
I connected it to a portable HDMI monitor as well as to a standard 4K TV and it worked fine. The sound was muted by default in some way (going to the movie menu enabled it). The volume control seems to be set high, had to lower it to
1 for my setup.
This model has however one big disadvantage - noise - depending on the disc used the noise changes, but overall it is quite audible and can be annoying when watching a movie so the player should likely be partially hidden in a cabinet or something similar.