system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is my 4K TV somewhat doubling the frame rate when the shows and games in question output to 1080p?

Basically, I've been noticing that some shows, including the iMPACT Wrestling channel(yes, they have their own TV channel) air their older stuff at 60FPS. I honestly thought that it was meant to be like that, but not only did I notice 60FPS with some stuff in games like WWE 2K22, but just earlier I noticed that Doom Eternal, a game on Switch capped at 30FPS, looked at times more fluid and at 60FPS. Occasionally, but still enough for me to notice.

So uh....how does this work?

Edit: Sorry, failed to mention it's a Smart TV.
gpt
Do you have motion smoothing or motion interpolation turned on for your tv? A lot of modern TVs will, be default, convert lower frame rate material to a higher frame rate by trying to add missing frames. If you can find it in the menus, try turning that off and seeing if that affects how everything looks.