Not a TIFU. This is a today your boss fucked up.

You don't have to do anything except point out that management decided not to give other coworkers the same bonus and everybody should fight to get what they deserve. In this situation, you don't have to be enemies at all, just say you feel bad and will help where you can to make sure everybody sees the unfair payment schemes

In the future, don't assume everybody makes the same amount, but do use that as a reason to know as much as possible about what they do make. It's the best way to stay competitive and know your worth. If you don't make as much as people who provide less, start looking for another job.