Streaming (Sunshine or Steam Link) does not capture Steam UI

Describe the bug

Right now, when streaming to another machine using Steam Link or sunshine, I cannot get the remote machine to see the Steam UI - it is simply not rendered in the stream.

That is, if I am playing a game:

snapshot

...and I hit the Steam button (or equivalent mapped to my remote controller), I will see this on the machine's physical display (captured with a PiKVM):

snapshot-2

...and after pressing "down", the UI becomes translucent:

snapshot-3

However, sunshine/Moonlight/Steam Link will display none of it. On the client machine will always see the game layer, without anything overlaid (although I can hear the UI audio):

snapshot

I have tried Steam Link settings, checked If sunshine is running with setcap, and also tried a number of different images (see #1260 to get an idea), but the issue happens on both deck and non-deck images, on GNOME or KDE.

Am curious to understand if this is a Wayland or AMD thing and if there are any fixes/workarounds.

What did you expect to happen?

I expected the stream to match the physical display.

Output of `rpm-ostree status`

State: idle
Deployments:
  ostree-image-signed:docker://ghcr.io/ublue-os/bazzite-deck-gnome:40-stable-20240611
                   Digest: sha256:26b268ec5de0c1618f0618855761b2da934614dfb060fd5d69ffed4fad14d2b9
                  Version: 40.20240611.0 (2024-06-11T16:59:32Z)
                     Diff: 460 removed, 193 added
          LayeredPackages: fio python3.11 python3.11-devel sunshine
                Initramfs: '"-I /etc/crypttab /etc/modprobe.d/amdgpu.conf /etc/modprobe.d/deck-blacklist.conf"' 

● ostree-image-signed:docker://ghcr.io/ublue-os/bazzite-deck:40-stable-20240611
                   Digest: sha256:6c59a228186bdbd3417580129702a9337c2edadac0206b0d4773df53dca58413
                  Version: 40.20240611.0 (2024-06-11T17:01:53Z)
          LayeredPackages: fio python3.11 python3.11-devel sunshine
                Initramfs: '"-I /etc/crypttab /etc/modprobe.d/amdgpu.conf /etc/modprobe.d/deck-blacklist.conf"' 

  ostree-image-signed:docker://ghcr.io/ublue-os/bazzite-deck-gnome:40-stable-20240611
                   Digest: sha256:26b268ec5de0c1618f0618855761b2da934614dfb060fd5d69ffed4fad14d2b9
                  Version: 40.20240611.0 (2024-06-11T16:59:32Z)
          LayeredPackages: fio python3.11 python3.11-devel sunshine
                Initramfs: '"-I /etc/crypttab /etc/modprobe.d/amdgpu.conf /etc/modprobe.d/deck-blacklist.conf"'

Hardware

                                            me@bazzite
     %%%%%%====%%%%%%%%%%                
   %%%%%%%%    %%%%%%%%%%%%%%             󱋩  bazzite-deck:stable 
  %%%%%%%%%    %%%%%%%%%%%%%%%%           󰣛  Fedora Linux 40 (Kinoite) x86_64
  %%%%%%%%%    %%%%%%%%%%%%%%%###           Linux 6.8.12-301.fsync.fc40.x86_64
  %%%%%%%%%    %%%%%%%%%%%%%######        󰅐  2 hours, 30 mins
  ==                  =======######       󰔠  Spawned on Feb 27 2024
  ==                  =========#####     
  %%%%%%%%%    %%%%%%%####======#####     󰾰  HCAR6000-MI2
  %%%%%%%%%    %%%%%#######=====#####     󰻠  AMD Ryzen 7 7840HS w/ Radeon 780M Graphics (16) @ 6.08 GHz
  %%%%%%%%%    %%%#########=====#####     󰍛  AMD Radeon 780M @ 0.80 GHz [Integrated]
  %%%%%%%%%    %%##########=====#####       5.15 GiB / 30.60 GiB (17%)
  %%%%%%%%%====###########=====######       384.69 GiB / 475.35 GiB (81%) - btrfs [Read-only]
   %%%%%%%%====#########======######      󰍹  1920x1080 @ 50Hz [External]
    %%%%%%%=====#####========######       󰖺  PiKVM Composite KVM Device
     %%%%###===============#######        󰖺  Mouse passthrough
      %#######==========#########        
        #######################             bash 5.2.26
          ###################               /dev/pts/1
              ###########                 󰏖  2717 (rpm), 79 (flatpak-system), 41 (flatpak-user)

                                           ● ● ● ● ● ● ● ●

Extra information or context

No response

ublue-os / bazzite