One thing you can do, if your hardware allows you a degree of shortcut customisation, to clear more of the onscreen reference clutter is to “double up” (or even more!) key commands into one button.
I’ve done this on both my Wacom and my Mac’s Touch Bar.
One button to Hide the UI + Reference images and one to bring it all back again.
To Hide = Shift+cmd+H+TAB
To Return = Shift+cmd+R+TAB
(On the Wacom for some unknown reason the TAB command has to come last in the sequence)
Hiding any other open undocked Panels at the same time as well though, is I’ve found, pretty much impossible as there is no consistency as to which panels will be open and undocked at any given time while I’m painting.
But if you do always have specific undocked panels open then I can’t see why you couldn’t set commands for them to add to the Hide/Show trigger sequence.
Maker Of Replica Macoys
Techie Stuff:
ArtRage 6.1.1 ~ 15" Macbook Pro ~ macOS 10.15.7 ~ 4 Core i7 3.1GHz CPU ~ 16GB RAM ~ Wacom Intuos4 M