Hi.
Can confirm this issue on Ubuntu 22.04 with Mate desktop env in X11 session.
No video acceleration is present.
When i try to start chromium in terminal i'm getting following output:
chromium-browser --use-gl=desktop --enable-features=VaapiVideoDecoder --disable-features=UseChromeOSDirectVideoDecoder
Gtk-Message: 09:12:41.908: Failed to load module "appmenu-gtk-module"
[26251:26418:1016/091242.099224:ERROR:object_proxy.cc(623)] Failed to call method: org.freedesktop.DBus.ListActivatableNames: object_path= /org/freedesktop/DBus: org.freedesktop.DBus.Error.AccessDenied: An AppArmor policy prevents this sender from sending this message to this recipient; type="method_call", sender=":1.137" (uid=1000 pid=26251 comm="/snap/chromium/2105/usr/lib/chromium-browser/chrom" label="snap.chromium.chromium (enforce)") interface="org.freedesktop.DBus" member="ListActivatableNames" error name="(unset)" requested_reply="0" destination="org.freedesktop.DBus" (bus)
Warning: vkCreateInstance: Found no drivers!
Error: vkCreateInstance failed with VK_ERROR_INCOMPATIBLE_DRIVER
    at CheckVkSuccessImpl (../../third_party/dawn/src/dawn/native/vulkan/VulkanError.cpp:88)
    at CreateVkInstance (../../third_party/dawn/src/dawn/native/vulkan/BackendVk.cpp:383)
    at Initialize (../../third_party/dawn/src/dawn/native/vulkan/BackendVk.cpp:269)
    at Create (../../third_party/dawn/src/dawn/native/vulkan/BackendVk.cpp:199)
    at operator() (../../third_party/dawn/src/dawn/native/vulkan/BackendVk.cpp:458)

Error: eglChooseConfig returned zero configs
    at Create (../../third_party/dawn/src/dawn/native/opengl/ContextEGL.cpp:53)

[26251:26522:1016/091244.462029:ERROR:udev_watcher.cc(98)] Failed to begin udev enumeration.


Information from vainfo:
vainfo 
libva info: VA-API version 1.14.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_14
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.14 (libva 2.12.0)
vainfo: Driver version: Mesa Gallium driver 22.1.0-devel for Radeon RX 5500 XT (navi14, LLVM 14.0.1, DRM 3.46, 5.15.0-50-generic)
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            :	VAEntrypointVLD
      VAProfileMPEG2Main              :	VAEntrypointVLD
      VAProfileVC1Simple              :	VAEntrypointVLD
      VAProfileVC1Main                :	VAEntrypointVLD
      VAProfileVC1Advanced            :	VAEntrypointVLD
      VAProfileH264ConstrainedBaseline:	VAEntrypointVLD
      VAProfileH264ConstrainedBaseline:	VAEntrypointEncSlice
      VAProfileH264Main               :	VAEntrypointVLD
      VAProfileH264Main               :	VAEntrypointEncSlice
      VAProfileH264High               :	VAEntrypointVLD
      VAProfileH264High               :	VAEntrypointEncSlice
      VAProfileHEVCMain               :	VAEntrypointVLD
      VAProfileHEVCMain               :	VAEntrypointEncSlice
      VAProfileHEVCMain10             :	VAEntrypointVLD
      VAProfileHEVCMain10             :	VAEntrypointEncSlice
      VAProfileJPEGBaseline           :	VAEntrypointVLD
      VAProfileVP9Profile0            :	VAEntrypointVLD
      VAProfileVP9Profile2            :	VAEntrypointVLD
      VAProfileNone                   :	VAEntrypointVideoProc


So, system has acceleration profiles.
And Apps like Mplayer, VLS are working fine.

Only chromium is not working.

Hardware with driver:
Radeon 5500xt with latest AMDGPU driver.
Installed with flags:
amdgpu-install --usecase=workstation -y --vulkan=pro --opencl=rocr,legacy