I thought I would point out that I do not have this issue on my work laptop. I can zoom in or out and the cursor position seems to remain synchronized with the font size changes. I experience the issue on my personal laptop only. Both laptops are the same: MacBook Air purchased in 2020, both running 10.15.7. I probably have more stuff installed on the work laptop, like Developer tools, etc.
The font in the text box appears perhaps to be Menlo in both cases.
I tried installing a font or 2 to see if that would have any affect, but that didn't seem to fix it.
I just noticed that the versions of Safari differ (screenshot via VNC):
I'm doing an update on my personal laptop now to see if that fixes it...
