The character set has been changed in the past, but these are all before the extension is deployed on Wikimedia. Now that it's deployed, changing the set is practically infeasible.

As you can see, Phabricator handles it well here https://w.wiki/7YP$, it also works on wiki and possibly elsewhere. The solution is to encode it if the character appears (only two additional chars, not much). On some platforms using angle brackets (less-than and greater-than chars actually) may help.

This is basically duplicate of T221016: Special Characters (like $ at the end) used in short URL not parsed e.g. in Twitter (should be avoided). You can use the alternative encoding instead if you want to avoid it: https://w.wiki/_vVe2