From my limited research and understanding, Nvidia makes Linux drivers, but they’re closed source. These work fine. They open sourced some stuff but not enough to really change much yet.
There are also FOSS drivers, but the performance for those vary.
Is this correct? Should I stick to proprietary drivers if I want consistent performance?
Yeah. The only two realistic options as far as drivers go are nvidia (the proprietary one) and nouveau (the free one). Nouveau lives in a niche where cards become obsolete before their full capabilities can be unlocked, so it is mainly useful for compatibility. It will still run a desktop just fine (assuming you're not buying cards on release day), but it is significantly less performant. You are setting money on fire by purchasing an expensive nvidia card just to run nouveau on it. You might get better performance out of your CPU's graphics system.
Things in desktop land are pretty robust and stable. Grab the nvidia driver from your package manager, reboot, and you should be solid. Laptops can add an additional can of worms. Most modern laptops use a system architecture where a low-power, battery-sipping Intel/AMD CPU graphics system drives the screen, and certain jobs can be offloaded to a power-hungry, high performance nvidia GPU (I believe laptops with AMD graphics are doing this now too, but nvidia has been this way for several years longer). The manufacturers call this "Optimus." I get what they're going for, but in my experience, this has caused a lot of headaches (like screen tearing because the iGPU and dGPU are out of sync). Specifically, you need to use a wrapper along the lines of Bumblebee to launch programs that you want to use the dedicated GPU. I haven't gamed on a laptop in years though. Things have probably improved a lot, specifically with the nvidia driver gaining support for XWayland.
On the other hand, the free AMDGPU driver runs smooth as butter, because AMD has spent near (over?) a decade working with the kernel developers on it. There is a small, optional, proprietary component called AMDGPU PRO, but general consensus (and my personal experience) is that there has been no need or benefit to installing it for years.
I think bumblebee is dead? the amd, nvidia, and intel drivers all have support for this natively and you just have to run graphics/compute apps through a driver specific wrapper. it's slightly more annoying for display outputs hardwired to the dgpu - the distro needs to inject a command after the the display manager starts - but it basically all works without fuss ime. I had more issues because I don't run a display manager and my distro is fairly diy, but I just stuck the appropriate command into an xprofile script and that sorted it.