I love that you have standardized headings now. A feature that I find very handy in Confluence is the ability to use shortcuts to change a heading level.
I'm on Mac so for me it's:
command+0: normal text (remove heading level)
command+1 (or 2 or 3): switch heading to that level.
Just like it works with the dropdown to select a heading level, the level will be applied to the line the cursor is on, if no text is highlighted.
Seems a small ask, hopefully it's something you can fit in soon! Shortcuts also improve accessibility for keyboard users.
Thanks for your time.