Hello @adcdam, please copy the contents of Steam Runtime Diagnostics from Steam (Steam -> Help -> Steam Runtime Diagnostics) and put it in a gist, then include a link to the gist in this issue report.
Thanks, https://gist.github.com/adcdam/26e0d0c2a05d6512378bb64aecf84f6c#file-gistfile1-txt-L83-L97 confirms that 32 bit Vulkan is indeed broken on your system because the Vulkan loader isn't finding a suitable driver for your video card, but beyond that it's not clear why that's the case.
This issue should be reported to your distro's package maintainer for mesa.
Nothing extracted yet.
Steam 1.0.0.78
Slackware current multilib
Steam beta
Amd rx6700 xt gpu
llvm 17.02
Mesa 23.2.1
vulkan-sdk-1.3.250.0
==========
VULKANINFO
Vulkan Instance Version: 1.3.250
Instance Extensions: count = 23
Layers: count = 16
VK_LAYER_FROG_gamescope_wsi (Gamescope WSI (XWayland Bypass) Layer (x86_64)) Vulkan version 1.3.221, layer version 1:
Layer Extensions: count = 0
Devices: count = 2
GPU id = 0 (AMD Radeon RX 6700 XT (RADV NAVI22))
Layer-Device Extensions: count = 0
when lauching steam from terminal i got:
Vulkan missing requested extension 'VK_KHR_surface'.
Vulkan missing requested extension 'VK_KHR_xlib_surface'.
BInit - Unable to initialize Vulkan!
its strange 64 bit engine games work but 32 bit one fail to start.