User blog comment:MisterWoodhouse/Social Activity, the 2010 Editor, and Unpausing Migrations/@comment-37108165-20201007135946/@comment-26939652-20201007141700

Nope. It's a "take it or leave us" deal on those points. Although I cannot find the staff post anymore, the 2010 editor is the replacement of the classic editor and fixing the design is basically your and your admin's problem. They won't do it for you, but point you to the help documents.

You can only access the 2010 editor by modifying your user preferences, so far it's not available via dropdown. It's named "Source editor" there and while it's definitely better than the 2017 source mode editor, it's still missing critical features for power users. It's been raised, but no response specifically on that, other then "we think it's good enough".