How to remove the spacing next to the last icon at the right of the menu bar that appeared after upgrading to Bartender 2
Bartender 2 2.0.1 fixes this, adding a preference in Preferences → Appearance:


  Right most menu bar gap
  Bartender 2 added a gap to the right of the menu bar when Notification Center was hidden, this is to maintain the default gap at the screen edge, a lot of users liked not having this gap, so this is now a preference under Appearance.