what does ? brilliant mean

I saw the game review and it said I have a ? amount of brilliants, please help

I don't have premium so I cant do the game review, so I don't know what it was

It's supposed to mean you played a brilliant move (possibly multiple), although rarely it can have false positives.

why doesnt it just tell you how many brilliants you played

It is a very good move that involves sacrificing a piece or leaving one free to take because it's poison in some way.

I reviewed one of your games that has one, though you didn't follow it up right and blundered two moves after.

Keep practising, you should get one free review a day, use it wisely and learn from what stockfish is telling you about your moves and what you should have played.

You could also look up some good speedruns where a master player is explaining WHY he is making the moves he makes. Eric Rosen has some good ones. Daniel Naroditsky had some good ones. Puzzles can help with pattern recognition. Hope that helps you improve.

The post game analysis is relatively low strength/depth and it can register if there is a potential brilliant (one that sacrifices material or allows material to be captured and is good or best) but it can't guarantee it will still meet that definition when a stronger review is run on the game.