I’ve written a bash script i’m using daily, maybe you can adapt it to your needs. I’m using pipewire-pulse. It’s probably not perfect but it does the job:

#!/usr/bin/env bash
DEVICE=$1

# read input, parse list of available sinks (outputs)
if [ "$DEVICE" = "pc" ]
then
	OUTPUT=($(pactl list short sinks | awk '{print $2}' | grep -i -E 'hdmi|samson|Targus' -v))
elif [ "$DEVICE" = "tv" ]
then	
	OUTPUT=($(pactl list short sinks | awk '{print $2}' | grep -i -E 'hdmi'))
else
	echo "No valid input (must be either 'pc' or 'tv')"
	exit -1
fi

# get all currently connected streams
INPUTS=($(pactl list short sink-inputs | awk '{print $1}'))

# change default sink (for new audio outputs)
pactl set-default-sink $OUTPUT

# switch sink for existing audio outputs
for i in "${INPUTS[@]}"
do
	pactl move-sink-input $i $OUTPUT
done

# use notify-send to send a visual notification to the user that the sink changed
notify-send -c info "Default sink changed" "Changed default sink and sink-inputs to $OUTPUT"