what is a TV made today that just has the lowest possible input lag?

Probably LG’s OLEDs. They’re pricey though. But I can’t remember the last time I used a TV with a noticeable amount of input lag, so long as they’re in game mode.

i also didn’t clarify, but I’d really like to not use a smart TV.

Better stick to your CRTs then. Alternatively you can just not use the smart functions (sometimes).