Get an AppleTV 4K. Use an app called Infuse to play back your video files from your local network/plex/jellyfin. Best Ui and remote on the market. No ads. No lag. No bullshit.

Connect it to an LG TV and disable the TVs internet connection and disable the Home Screen on startup. You basically have a dumb tv.

I got an LG OLED (GX), with plans to get an AppleTV. However WebOS worked well enough, and it is even better when rooted. I can watch YouTube ad-free and Emby. I don’t use too much else.

I would go for a streaming stick because it’s easier to replace it. I used a Xiaomi 4K stick and was quite happy with their performance though. If you need to upgrade your streaming devices, it’s much easier you don’t have to buy another TV.