SUMMARY
There is a QTWayland that has been solved in Qt 6.3.0 for X11. Is related to how QTWayland works in some distros when looking for "libvulkan.so" library. Some Linux distros, like openSUSE or Fedora, name that library as "libvulkan.so.1", so is not find by QT. 
Issue is identified and solved here https://github.com/qt/qtbase/commit/888b75aa12e2cf35ee760bcf5cb1ed60fe0c0770 too and could be applied easily to Qt 5.15.x.

Please fix it ASAP, cause many users have issues in applications under Wayland when their distros have not "libvulkan.so" but "libvulkan.so.1" and it's really a headache for programmers to detect what's happening.

Thank you

STEPS TO REPRODUCE
1. Launch an application installed from some distros repositories that needs "libvulkan.so"

OBSERVED RESULT
Usually, at console, application will show some message similar to:
initInstance: No Vulkan library available
Failed to create platform Vulkan instance

despite, in fact, Vulkan related packages are installed

EXPECTED RESULT
To search for "libvulkan.so.1" too and do not fail

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20231016
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.11
Kernel Version: 6.5.6-1-default (64-bit)
Graphics Platform: Wayland
Processors: 24 × AMD Ryzen 9 3900X 12-Core Processor
Memory: 31.2 GiB of RAM
Graphics Processor: AMD Radeon Graphics
Product Name: B550M Phantom Gaming 4

ADDITIONAL INFORMATION
As a workaround, if user guess that this is the issue he has, he can launch application preceding it with this environment parameter:
QT_VULKAN_LIB=/path/to/libvulkan.so.1 name_of_application_needing_libvulkan.so