I found this forum very interesting, as it's a topic that not many people understand from their game analysis.
On Chess.com, a "brilliant" move is one that breaks expectations, usually involving an unexpected sacrifice or a very unconventional move that radically changes the position. However, many players mistake these types of moves for genius, when in reality, brilliance, in and of itself, can be a disguised form of error.
Being brilliant in chess can be a mistake because not every brilliant move is good in practical terms. The Chess.com system marks a move as "brilliant!!" if it's difficult to find, it's not a primary recommendation from the engine, and it has an immediate positive impact on the evaluation. But that doesn't mean the move is objectively superior or that it will work in every situation. Often, brilliant moves require a chain of subsequent precise moves that, if not executed perfectly, can turn an advantage into a catastrophe.
On the contrary, "brilliant!" moves, although Chess.com, could be understood as those marked as "the best," which coincide with the engine's main recommendation and are fully justified by the position. These moves are not only strong, but also solid, strategically coherent, and sustainable in the long term. They don't require the opponent to make a mistake. They work even if the opponent plays precisely.
The difference lies in the purpose: a brilliant move surprises; a brilliant move wins. The former may impress in an analysis or in a rapid game, but it often stems from overconfidence, the pursuit of spectacle, or the desire to force a premature outcome. For this reason, a brilliant move is often followed by bad decisions or, in its counterpart, is the result of a mistake. I don't know if I answered your question exactly, but I think a good summary
how come player loose even after brilliant moves