I’m mostly echoing what’s already been said, but I have a preset in Handbrake for this, which works fine on most TVs I’ve tried from the last 10 years (possibly 15 by now) and therefore should have no problem running on any computer. I often (for work reasons) prepare video footage for looped playback on TVs and projectors at numerous places - so “TVs I’ve tried” is a larger number than it might initially sound like.
It’s roughly along these lines (as I appear to have emailed someone about before):
"H264 mp4. 1920x1080. 25 or 30fps, or similar (appropriate to source material). Constant bitrate <=12mbps. 8mbps is generally universally compatible, though you should be able to get away with 10-12mbps on newer TVs with newer USB sticks.
AAC audio 192kbps, though lower is fine.
Use same samplerate as source (i.e. 44khz 48khz etc)
If you’ve got settings for encoding profile, Main and Level 4.0 should work.
If individual files are small enough (<4GB), format the USB stick as FAT32. Otherwise NTFS. EXT2 will work on a lot of TVs, but you’ll have trouble with some computers. Exfat may work on newest tellys, but won’t on anything more than a few years old, so safe option is not to use it."
NTFS was around in the 1990s, exFAT is from the 2010s - and I think was also caught up in some sort of copyright/proprietary shit for another 10 years. There are brand new 2025 TVs which still won’t read exFAT.