PulseAudio data shows 6 HDMI outputs but they are not available and there is no indication of which
output is connected to the monitor
Plasma audio settings GUI must be showing available profiles only
pavucontrol would show profiles as (unplugged)(unavailable)
ALSA data is also showing 6 HDMI outputs with no connections to a monitor
(see data from another recent post showing HDMI devices detected in ALSA correctly)
I suggest you check HDMI outputs are not muted in ALSA mixer
alsamixer --card=HDMI
But it is more likely a problem with the cable connection to the Monitor
I suggest you try using a different HDMI / DisplayPort output on the GPU
and a different cable