USB Headset works with pulseaudio run in terminal but not as a service

I have a MPOW USB Headset which works (both speakers and microphone) when starting Terminal and entering:

pulseaudio -k
pulseaudio

However, when I start pulseaudio like this it doesn't work:

systemctl --user start pulseaudio.socket
systemctl --user start pulseaudio.service

When running just pulseaudio however I have to keep the Terminal window open. As soon as I stop pulseaudio, sound is gone again (which makes sense).

How can I run pulseaudio in the background and still have sound and microphone working?