Thanks. Could we communicate about this privately? If you are willing, please send me contact information at david.a.foster at nc.rr.com.
I luckily had an old backup of my Themes, which I restored, and my site looks like it is back to normal. Use Any Font is deactivated, and I am scared to ever activate it again.
If this is helpful… in the block editor, normally when I look at the dropdown menu for Font Family there were about a dozen different fonts (including Default). When I activated your 6.3.04 plug in this morning and most/all fonts in my site changed, I looked at this same dropdown menu, and there were just two: Default, and Playbill (which was a font I had imported with UAF.) Now after restoring my theme, its back to how it was with a dozen font options.