Thanks @JohnAD, and an update in case someone starts questioning the same. It's not a Nim issue whatsoever. (I couldn't change my email and had to create a new account, deleted the previous one).
So far, the issue is seemingly with the Windows Terminal. It might be even worse with older versions. Those specific characters I posted and some other ones in the Unicode Math blocks such as Math Italics, Math Sans, Math Bold etc, are all showing extra spaces when you _echo_ them (i.e. executing them from the terminal in VSCode, which I believe uses Windows Terminal. Other characters like the Greek alphabet are doing just fine. I didn't need any special encoding nor setting besides _chcp 65001_. These issues are seemingly being carried over since before Unicode was implemented, and the encoding used by Windows Terminal might need a fix.
