I found out by checking installed packages using yay vulkan and saw that vulkan-nouveau (and lib32 version) where installed and lib32-nvidia-utils where missing (nvidia utils was installed)
Installed lib32-nvidia-utils, removed both nouveau vulkan packages and clean dependencies using yay -Yc
After reboot, it was working.
On KDE you can check vulkan in the tool that is linked in the about page in the settings. But maybe only 64bit version, steam uses 32bit.