Apparently the bug that causes the Delphi IDE to not store its position correctly when placed in full screen on a secondary monitor to the left of the primary monitor (which is my setup at home and at work) still hasn’t been fixed in Delphi 10.4. Luckily the work around of editing the desktop settings still works.
For Delphi 10.4 these files are stored in
C:\Users\<YourName>\AppData\Roaming\Embarcadero\BDS\21.0