Well not directly in discourse. I had a member who inquired back when discourse didn’t have a mute/ignore feature. He created a tamper monkey script that added the option. Now to add users you had to edit the script. He had other bling as well as it would decorate the Op, Admin/Mod & special groups. It would hide the post with a drop down option to open.
He was asked if you could block a mod. To which he said yes. But didn’t recommend it as a mod may post useful information.
The old script is broken now as it was made over 7 years ago now.