A driver allows games to interface with the graphics hardware, enabling accelerated performance for example. This “app” provides additional functionality on top of that (I don’t know what, but GeForce Experience it replaces provided things like recording gameplay videos etc.) which is not strictly required and, it seems, hurts gaming performance.
As for getting the latest drivers, you can do it manually by going to nVidia’s website and download them, or rely on Windows update to give you reasonably recent drivers.
I do not have info like that, just lamenting that manufacturers (not just AMD) are raising prices of their tiers. The GTX 1070 launched in 2016 for USD 379, GTX 1070 Ti in 2017 for 399. Adjusted for inflation, they are $506 & $522 in 2025 dollars, so expecting there are still some room for reduction, even if manufacturing costs might have risen quicker than inflation, for the $599 price is not unreasonable IMHO.