

AMDVLK was the official AMD open source driver rarely anyone used
Depends, if you installed both AMDVLK and RADV, AMDVLK would be the default unless you changed your default Vulkan icd loader. Maybe distros where you don’t have to do a lot of DIY and more focused in gaming then RADV was the default. But other distros went with upstream defaults.
nopaystation is safe, you get the titles directly from sony’s servers. it’s the sony equivalent of ciangel/freeshop back when you could do that on your 3ds. it’s only for digital games, so i don’t think armored core 4 ever got a psn release so you’d need to get the .iso for it anyways.