Now, add the same filter on the home page in the category: "Most active topics" 



Another idea:
On the user page, there may also be a scroll bar, similar to the one at the top of the homepage, with the latest posts in which that user was mentioned. Kind of similar to what happens in your Telegram bot.
More interesting would be to make an audible signal when a mention occurs. It would be a way to notify the user who is on the PC. Of course, the sound signal can only be active if it is indicated by the user.

Complicated?