This isn't a guide, just something i think may help. To install Steam on an Arch-based distro in most of the cases a simple sudo pacman -S steam will do just fine.
The installation will ask you to select a valid vulkan package from a list. And in most of the cases that's just fine... most of them.
Then you have your very "picky" old nvidia GPU which works only with a specific old nvidia driver and if you try to install anything else, there will be a conflict. Now you can try to remove the old (working) drivers and try your luck. But looking online i find a simple way to skip this passage and install Steam.
sudo pacman -S steam --assume-installed lib32-vulkan-driver
750 specifically was special because it was Maxwell architecture that Nvidia used on an "old" GPU brand line.
Hence the CM 5.0 instead of 3.0.
Mine was on the 580 something driver with CUDA 13.2 when I removed it from my server a couple of weeks ago.
I had a 750 years and years ago and had forgotten this. It felt like I was getting a kind of sleeper card at the time. Not that it was ever that powerful.