Your page listing issues/limitations asks users specifically to report any additional limitations we find here.
Version is 2.7.15 (prod, win32) Rev 8352e23, Sync Ver 3, Prof Ver 41
Windows 10 21H1 - 10.0.19043
Tabs set in markdown are blown away in the rich text editor. The rich text editor appears to not support tabbing at all. In fat this editor also does not support them either
So structured lists where theres a title header, new line, tab sub header 1, new line, tab tab sub item 1, new line, tab tab sub item 2, new line, tab sub header 2, etc
are not possible in rich text but are in markdown