https://support.chess.com/en/articles/8572705-how-are-moves-classified-what-is-a-blunder-or-brilliant-and-etc
a brilliant move is better than a great move
Not necessarily.
And you base this on what?
Martin_Stahl gave a link, read that, don't spread misinformation.
I got a brilliant move playing the haxo gambit opening. I sacrificed my Bishop F7 forcing the king to move and that was considered a brilliant move.