In addition to all the suggestions - check out modding databases like nexusmods or whatever. Many older games that would not fit your definition have graphical mods that will make your GPU work.

Personally I’ve played modded stalker, fallout, elder scrolls. Hell, you can make Minecraft look absolutely amazing, but it’s a pain to set up properly. You’ve mentioned you’re not into horror games, some games also have total conversions available that do a some genre bending too.

Cyberpunk is not that old, but it’s one of the best looking games ever made IMHO.

Witcher 3, also potentially with mods.