Yes, there should be more options when notifications are revamped, although that won’t be for a while.
Stupid question, but I’m not a PC user: what are you expecting middle clicking to do, open it in a new tab?
Maybe worth a bug report. Sounds similar to https://forum.inaturalist.org/t/new-account-settings-page-says-anyone-can-add-observation-fields-to-my-obs-but-actually-only-i-can/19430