You are right because Tottenham hopes that next season can be much better and maybe they can compete for the Premier League title with several other strong teams. Ange Postcoglou's record in the Premier League with Tottenham is not that impressive because they have suffered quite a lot of defeats and this can make them fall further behind next season if they don't try to make adjustments by recruiting a new coach.
But one thing to remember, that replacing a coach does not necessarily make a team much better, as happened with Man United so Tottenham need to think about a definite step by bringing in a coach who is much better than Ange Postcoglou himself because if not, maybe next season will not be much better.
I don't see a better season than this for Tottenham. They winning Europa League, and qualify for the UCL, though they had terrible performance and finished at 17th. However, we know so well how Europa League is a major trophy, and not many teams owned it.
It would better if they gave Ange another chance, but their owner is just an impatient person, and sacked him after a dramatic won in the final of Europa League. I'm surely they will get a factory reset next season. Play badly, no achievement, and finish at the bottom table.
You cannot come to conclusion on what will be their fate next season just because they sacked a coach that failed to improve the team performance and won Europa League by luck. It was the same thing that happened to United last two seasons during Ten Hag time. Instead of United sacking Ten Hag for the poor performance of the club, they praised him for winning City in the FA Cup finals and supported him to get new players of his choice but what happened at the end. I don't see anything about the sack of Ange