How do I find the motion enhancement/anti judder option in my TV?

Sorry in advance - I know this is for gaming and Xbox but I literally could not find a single resource on Google.

It's a TCL c635 and I wanted to know how to find the motion clarity/smoothening options and see what it's like to play games at 120hz.

For some reason, the option is not there right now but was yesterday and for the first time I played flight simulator at 120fps! I think between then and now, something must have changed as the motion options are either not there at all under advanced settings or there is only one option for retaining cinema quality or something along those lines.

So... Do I have to get out of game mode or something to get the 120hz anti judder enhancement back? Is the Xbox preventing that setting from showing up? Do I need to switch to certain picture mode or turn off game mode on my TV to enable the anti judder/motion smoothening options?

This is really frustrating as it was there one day and after I put my TV into game mode and tweaked everything including HDR to my own preferences, I now don't have motion smoothening or can't find it.

Yellphh!

:)