Different tools count different things, so small mismatches are normal:
MyRedLink counts redirects: each time a person opens your short link and is sent to the destination.
Google Analytics counts page views on your site, after its own filtering and consent rules. Visitors who block analytics show up in MyRedLink but not GA.
Link previews are not clicks. When Reddit or Discord fetch your link to draw a preview card, that is a bot request, not a person, and is served a lightweight response.
Directionally the numbers should track each other. If they wildly disagree, check that your destination page actually has your analytics installed.