Comment by encypruon

I think I finally managed to disable tracker-miner on xfce.

  systemctl --user list-unit-files | grep -o "tracker-\S*\.service" | xargs systemctl --user mask

...wasn't enough. What did the trick was unchecking the remaining two entries in the "session and startup" settings dialog. Good riddance. It was the number one reason for my notebook heating up and draining battery.