I'll get right to it; My computer is an Apple Macbook Pro MacOS 10.15.7
I have just updated to newest Indesign (2021) and software was functioning normally.
Got to last page (36 pages, A5) and inserted an image, which was first and only image. Still seemed normal.
Edited a pre-existing text box to a more decorative font, then tried to apply a stroke.
Initially it would simply take 5 or so minutes to load (pinwheel), now has just started crashing, or applying it with visual distortions (see below), and cannot be edited without significant delay or crashing
I have restarted software and computer.
I have lowered display to 'Fast' (lowest setting).
I have cleaned out my disk.
There doesn't seem to be any other tools I can use to speed up performance (no on/off live drawing, no on/off hyperlink verification, no on/off save preview images, and etc).
Worringly it seems to be getting worse each time I open document.
Any help would be very much appreciated!
I even deleted the image, it appears that the stroke application is the issue.