Cemu

Cemu/Vulkan was working properly with Steam Overlay in 2021, however, it no longer works for some reason. But when you switch to OpenGL instead of Vulkan, the Steam overlay immediately works again.

Nb1: For reference, other non-Steam games that utilize Vulkan are currently able to access the Steam Overlay properly

Nb2: The Steam Overlay is unfortunately a necessity for those using Steam Controllers and/or SteamLink, given its access to the controller configuration and Link settings, along with the ability to exit the game/Cemu without having a keyboard

Nb3: I've tested this with all versions of Cemu between 1.24.0-1.27.1, and all Cemu versions have the same result, an inaccessible Steam Overlay