Counterpoint: at least it's not Windows 11. I don't care if it's prettier if it's less functional and more buggy. Plus, I hear it steals design cues and features from KDE, although it seems that stealing commonplace features from Linux Desktop Environments is think that's been ongoing, if I remember correctly.
Not sure when they added it, but you can get dark mode on it. The path for me: C:\Program Files (x86)\Microsoft SQL Server Management Studio 19\Common7\IDE the file you need to modify is ssms.pkgundef and the line has a comment above it that says //Remove Dark Theme
Just comment the line. Boom
Edit: I have a very new edition of ssms (some version of 19) so YMMV