Not true. Here at chess.com, a brilliant move is a decent sacrifice.
They changed the definition back in 2021.
Brilliant
Brilliant Moves are always the best or nearly best move in the position, but they are also special in some way.
We replaced the old Brilliant algorithm with a simpler definition: a Brilliant move is when you find a good piece sacrifice.
There are additional conditions:
You should not be in a bad position after a Brilliant move
You should not be completely winning even if you hadn't found the move.
We are also more generous in defining a piece sacrifice for newer players compared to those who are higher-rated.
A brilliawnt move is a much better move than a great move.