The 580 legacy driver is DKMS, so there shouldn’t be any maintenance beyond what is already required for any other DKMS driver, which would be handled by pacman anyways. So no need to worry about kernel updates

If you’re adamant on keeping those GPUs, Nouveau would be the only path forward - eventually paired with NVK for Vulkan acceleration once that’s good enough for primetime. Pascal was dropped because of the lack of a GSP module as well as age, so the newer Nova driver won’t support it either

Right now: Deus Ex, specifically the Adam Jensen games

in the Near future, best case we get Cyberpunk 2077, worst case we get Horizon Zero dawn’s Faro Plague