Terrible performance in Linux Mint compared to Windows

I have an older computer that I use for some simple games. Its I5-7400, GTX-1050, 12GB memory, and an SSD - not new by any standards, but most of the games I'm playing are a decade old or more. I switched to Linux Mint today, since I don't want to use Windows 11, but the performance on Mint is terrible compared to Windows 10. For example, in Portal 2's native Linux version, I get like 10 fps in the title screen. War Thunder doesn't even launch. The drivers are set to Nvidia's proprietary drivers via the GUI. Am I missing something? I'd really rather not switch back to Windows.

Edit: VulkanInfo is saying, "ERROR: [Loader Message] Code 0: loader_scanned_icd_add: Could not get 'vkCreateInstance' via..."

It also seems to only be showing my CPU, not gpu? Not certain, since I don't unstand a lot of the details, but it says, "deviceType = PHYSICAL_DEVICE_TYPE_CPU".

Edit 2: turning off secureboot fixed it.