I had some issue, probably related to an install oddity. PR did not see the "Regular" variation on the font, but Windows did.
This is a variable type font face, which can be installed entire-family-from-one-file, so each variation from its own file.
In the "problem" install, setting both graphics text and caption text to Public Sans Black, they are very different. Black is much thicker.
From Windows, I uninstalled all of Public Sans and then installed just Public Sans Regular from its solo file.
It is available in PR for both graphics and caption text, but this time they appear the same. So I suspect that PR Caption text, which does not support all fonts supported by graphics text, may not handle variable fonts? But I really don't know.