https://bugs.winehq.org/show_bug.cgi?id=50252
--- Comment #9 from Rafał Mużyło galtgendo@o2.pl --- ...so, it would seem that my initial problem in this bug wasn't quite a regression - it was more of a minor user error mixed with wine's behavior change.
As you may see in that registry file, for historical reasons I had both HKLM\Software\Microsoft\Windows NT\CurrentVersion\FontSubstitutes and HKCU\Software\Wine\Fonts\Replacements set up with mapping IPA Mona families to respective MS families. In my defense, all those years back when I've set it up, I couldn't find any proper documentation for this and for most cases just having FontSubstitutes worked. That was actually the only set of keys that I've had set up initially and it worked in most cases. Far more recently (IIRC, within last year) I've noticed that one of the cases that didn't, started to work with Replacements. But things continued to work with both of those set.
It would seem this ended with wine 5.21.
After removing relevant FontSubstitutes keys, regedit no longer has this problem with missing glyphs.
Tahoma also seems to act properly in the Font Viewer.
But (as that had been unrelated problem) Webdings are still clipped. (also that program seems to handle DejaVu Math TeX Gyre oddly, but that might just be a bug in the program - after all, that a somewhat specialized font, so I wouldn't be surprised if it had slightly odd metrics)