From what I've seen using the exclamation mark gives the best experience as the person clicking the link stays within their same instance, rather than going to the instance the community is hosted on. Also it looks like how you linked the community made the system think it's an email address so it doesn't work that way.

example: !support@lemmy.world

!community@instance.tld is best

The exclamation mark is extraneous and creates confusing a visual indicator as to whether a link is to the hosting instance of the community rather than a link to the federated copy on whatever instance you're on. It works one way in some circumstances and the opposite way in others. And it won't work at all for people who are on an instance that hasn't federated with that community. It has in fact been depreciated by the main devs of Lemmy but that's only documented in comments to github issues.