I'd recommend supporting the Idea with an upvote and explaining your use case in the comments.
Our product team uses that forum to collect ideas on how we can improve the product for our customers.
Product pays particular attention to the top voted ideas & takes them into consideration along with other feedback channels as well as their own vision to understand what features will be most valuable.
So apart from the notifications sidebar there is no place to see all mentions? What if many of these mentions are not in the service hub but scattered around within companies, contacts, tickets, etc.? I sometimes get very backed up on responding to mentions and its nearly impossible to keep track of them all in the sidebar.