You probably want a computer monitor rather than a TV; monitors will prioritize latency which is important for music production.

Related, many modern TVs have "game mode" which prioritizes video latency, with the loss of some of the algs being available.

RTINGS actually tracks this, with most being comparable to monitors at the same refresh rate, while in game mode (around 10x faster than non-game mode). [1]

4k@120Hz with VRR is even available in < $1k TVs these days!

And, for audio latency, unless you're using the built in speakers, it's fairly trivial to make the video and audio paths independent.

[1] https://www.rtings.com/tv/tests/inputs/input-lag

Huh? You are confusing video refresh rate with audio latency.

Does the stuff on the screen not need to also be low latency when recording live instruments?

Irrelevant.