Data in post #1 shows pipewire-alsa installed, to use PipeWire as default output for ALSA devices (onboard audio and USB headset)
If metapackage manjaro-pulse is working as expected it should install 3 packages:
pulseaudioto replacepipewire-pulsepulseaudio-alsato replacepipewire-alsapulseaudio-bluetooth
To check the default ALSA output
aplay -L
If pulseaudio-alsa is installed response should look like this:
default
Default ALSA Output (currently PulseAudio Sound Server)
Response should also show ALSA audio playback devices:
DEV=0 - nVidia HDMI
DEV=1 - Onboard Audio
DEV=2 - Headset
I suggest clear old user configuration settings for PulseAudio in home folder and restart pulseaudio.service
rm ~/.config/pulse/* ; systemctl --user restart pulseaudio
To check audio cards detected in PulseAudio (or pipewire-pulse)
pactl list cards
and audio streams from youtube to PulseAudio (or pipewire-pulse)
pactl list sink-inputs