There are Cup Finals and cup finals in football. Cup Finals, capital C capital F, are finite and get played at vast arenas, with much fanfare and a trophy at the end; cup finals, lower case and metaphorical, are different.
A cup final can involve two teams in the bottom four come April; or a manager who is without a win in 10 games.
Manchester United have played two cup finals already this season, and lost them both. The first was away to RB Leipzig in the last Champions League group game, needing a draw to progress.