One setting I know of that even remotely comes close to try and do anything like this is virtual memory. If you lower that in windows you lower the risk of windows trying to use that for some strange reason instead of ram. I’m not saying windows would do that btw, it would be highly unlikely. Also, you can update and check your video card drivers if anything can be tweaked there

Increase texture resolution till your vram is saturated and it has to flow over into ram.

You dont, it’ll use as much as needed. And if you have a dedicated GPU, VRAM on the GPU takes priority over using (additional) system ram

Not how it works. You honestly want your system using as little as possible.

Ram usage depends on the application/game and how many background tasks/programs you have running. Programs and games only use X amount of ram depending on how demanding the application is

A modern operating system should use the available RAM for buffers and cache.

I have 16 gb and Eacape form Tarkov is the only game that used all of it

Actually this is good, means that you have sufficient ram in your system.