Bold Font Rendering issue in Safari and Mail in Sonoma

MacBook Pro 2019

Sonoma 14.5

This is STILL an issue after a complete HD erase, reformat, and clean OS install so I'm stumped. Spent an hour on the phone with support and they are stumped.

Basically any font in Safari or Mail with font-weight:bold; is rendering strangely. Also in Safari Settings > Advanced, the Style sheet says, "none selected" so not sure if that's related.

Resetting default fonts in Font Book did not resolve the issue.

I found several examples of developers struggling with this:

• https://stackoverflow.com/questions/9450706/safari-font-weight-issue-text-too-bold

• https://stackoverflow.com/questions/9081221/safari-css-bold-font-too-bold

Screenshots: