Steam remote play hardware decoding not working

Hello,
I’m using openSUSE Tumbleweed on an HP Envy x360 laptop with an AMD Ryzen 5 APU. Hardware video decoding is working on my machine (VLC, mpv, Firefox), using VA-API. Here is a list of related packages:

S  | Name                   | Summary                                                   | Type
---+------------------------+-----------------------------------------------------------+----------
i+ | libva-drm2             | DRM backend for the Video Acceleration API                | package
i+ | libva-drm2-32bit       | DRM backend for the Video Acceleration API                | package
i+ | libva-glx2             | GLX backend for the Video Acceleration API                | package
i+ | libva-glx2-32bit       | GLX backend for the Video Acceleration API                | package
i+ | libva-utils            | A collection of utilities and examples to exercise VA-API | package
i+ | libva-wayland2         | Wayland backend for the Video Acceleration API            | package
i+ | libva-wayland2-32bit   | Wayland backend for the Video Acceleration API            | package   ← I had to install manually this one, despite having Steam installed by zypper and being on KDE Wayland
i+ | libva-x11-2            | X11 backend for the Video Acceleration API                | package
i+ | libva-x11-2-32bit      | X11 backend for the Video Acceleration API                | package
i+ | libva2                 | Video Acceleration API                                    | package
i+ | libva2-32bit           | Video Acceleration API                                    | package
i+ | Mesa-libva             | Mesa VA-API implementation                                | package

Nevertheless, when I use Steam remote play with hardware decoding active, I only get a black screen for a few seconds before the streaming client closes.
I guess there is a dependency problem, because in the Steam Runtime Diagnostics I get (reporting only "x11/vaapi" and "va-api_drivers" ):

[········]
        "x11/vaapi" : {
          "messages" : [
            "libva info: VA-API version 1.20.0",
            "libva info: Trying to open /usr/lib/dri/radeonsi_drv_video.so",
            "libva info: va_openDriver() returns -1",
            "vaInitialize (va_display, &major_version, &minor_version) failed: unknown libva error (-1)"
          ],
          "renderer" : null,
          "version" : null,
          "issues" : [
            "cannot-draw"
          ],
          "exit-status" : 1
        },
[········]
      "va-api_drivers" : [
        {
          "library_path" : "/home/lorgar/.local/share/Steam/ubuntu12_32/steam-runtime/usr/lib/i386-linux-gnu/dri/dummy_drv_video.so",
          "version" : "libva1"
        }
      ],
[········]
        "x11/vaapi" : {
          "messages" : [
            "libva info: VA-API version 1.20.0",
            "libva info: Trying to open /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so",
            "libva error: dlopen of /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so failed: /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so: wrong ELF class: ELFCLASS64",
            "libva info: Trying to open /usr/lib/pressure-vessel/overrides/lib/i386-linux-gnu/dri/radeonsi_drv_video.so",
            "libva info: va_openDriver() returns -1",
            "vaInitialize (va_display, &major_version, &minor_version) failed: unknown libva error (-1)"
          ],
          "renderer" : null,
          "version" : null,
          "issues" : [
            "cannot-draw"
          ],
          "exit-status" : 1
        },
[········]
        "x11/vaapi" : {
          "messages" : [
            "libva info: VA-API version 1.20.0",
            "libva info: Trying to open /usr/lib/pressure-vessel/overrides/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so",
            "libva info: Found init function __vaDriverInit_1_20",
            "libva info: va_openDriver() returns 0",
            "Testing H264Main decoding"
          ],
          "renderer" : "Mesa Gallium driver 23.2.1 for AMD Radeon Vega 8 Graphics (raven, LLVM 17.0.3, DRM 3.54, 6.5.9-1-default)\n",
          "version" : null
        },

It appears that the version of libva shipped with openSUSE isn’t compatible. Is there a libva1 available? Am I missing something else?
Is someone else using hardware acceleration with an AMD APU for Steam remote play on openSUSE?

For completeness, here is the output of vainfo:

Trying display: wayland
libva info: VA-API version 1.20.0
libva info: Trying to open /usr/lib64/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_20
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.20 (libva 2.20.0)
vainfo: Driver version: Mesa Gallium driver 23.2.1 for AMD Radeon Vega 8 Graphics (raven, LLVM 17.0.3, DRM 3.54, 6.5.9-1-default)
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
VAProfileJPEGBaseline           : VAEntrypointVLD
VAProfileVP9Profile0            : VAEntrypointVLD
VAProfileVP9Profile2            : VAEntrypointVLD
VAProfileNone                   : VAEntrypointVideoProc