No HDMI audio after suspend to RAM (AMD Ryzen 9 6900HX, Kubuntu 22.10)

I installed a new Kubuntu system on a Beelink GTR6 (AMD Ryzen 9 6900HX). Everything is running fine. Except that after a wakeup from a suspend to RAM, there is no more Audio coming through the loudspeakers in my HDMI monitor, although every widget, audio control etc still say that audio is playing. I have not yet found any way to reactivate the audio, except of a complete reboot of the system.

I am not sure, how to debug this. I have tried very many recommendations from the net (to restart pipewire, wireplumber, disconnect the HDMI device, open amixer, ...), but none worked.

Is there anyone who can help me fix this issue?

Thanks

Michael

Output of wpctl status:

PipeWire 'pipewire-0' [0.3.58, michael@DesktopMB2, cookie:752624561]
 └─ Clients:
        32. pipewire                            [0.3.58, michael@DesktopMB2, pid:2214]
        33. WirePlumber                         [0.3.58, michael@DesktopMB2, pid:2213]
        34. WirePlumber [export]                [0.3.58, michael@DesktopMB2, pid:2213]
        54. xdg-desktop-portal                  [0.3.58, michael@DesktopMB2, pid:2735]
        55. Plasma-PulseAudio                   [0.3.58, michael@DesktopMB2, pid:2489]
        56. wpctl                               [0.3.58, michael@DesktopMB2, pid:2975]

Audio
 ├─ Devices:
 │      40. Rembrandt Radeon High Definition Audio Controller [alsa]
 │      41. Family 17h/19h HD Audio Controller  [alsa]
 │  
 ├─ Sinks:
 │      31. Family 17h/19h HD Audio Controller Pro [vol: 1.00]
 │  *   46. Rembrandt Radeon High Definition Audio Controller Digital Stereo (HDMI 4) [vol: 0.55]
 │  
 ├─ Sink endpoints:
 │  
 ├─ Sources:
 │  *   45. Family 17h/19h HD Audio Controller Pro [vol: 1.00]
 │  
 ├─ Source endpoints:
 │  
 └─ Streams:

Video
 ├─ Devices:
 │  
 ├─ Sinks:
 │  
 ├─ Sink endpoints:
 │  
 ├─ Sources:
 │  
 ├─ Source endpoints:
 │  
 └─ Streams:

Settings
 └─ Default Configured Node Names:
         0. Audio/Sink    alsa_output.pci-0000_05_00.1.hdmi-stereo-extra3
         1. Audio/Source  alsa_input.usb-0b0e_Jabra_SPEAK_510_USB_501AA56BAD8E020A00-00.mono-fallback

I cannot post the full output of pw-cli ls (claims that it looks like spam). Here a small extract:

    id 42, type PipeWire:Interface:Port/3
        object.serial = "52"
        object.path = "alsa:pcm:0:hdmi:0,3:playback:playback_1"
        format.dsp = "32 bit float mono audio"
        node.id = "46"
        audio.channel = "FR"
        port.id = "1"
        port.name = "playback_FR"
        port.direction = "in"
        port.physical = "true"
        port.terminal = "true"
        port.alias = "BenQ EX3410R:playback_FR"
    id 43, type PipeWire:Interface:Port/3
        object.serial = "50"
        object.path = "alsa:pcm:0:hdmi:0,3:playback:playback_0"
        format.dsp = "32 bit float mono audio"
        node.id = "46"
        audio.channel = "FL"
        port.id = "0"
        port.name = "playback_FL"
        port.direction = "in"
        port.physical = "true"
        port.terminal = "true"
        port.alias = "BenQ EX3410R:playback_FL"

There is no obvious change to the output of pw-cli nor wpctl after a suspend-to-RAM (and non-working audio).