I see it too from your point of view, the sudden sack somehow felt so off and may possibly throw the team off balance awhile even though he was not doing so well with them, but if a new coach comes, it will be tough work for him amd I hope they are not expecting some magic too else they should be ready for some very messy season, it would have been easier with ten Hag to turn a new leave than it will be now starting all over with a new coach.
I know some will think that this decision will be a tough one for the team, which even as so, I think is the best for the team. Because if Erik ten Hag was able to do something better, then they would have seen a bit of change. Even though we all know that the management also sold most of their players, still, Erik was not capable of being a coach, considering his performance in Manchester United and also in Bayer Leverkusen. So, sacking him is the best decision. If they get a better coach, it will take some time for him to adapt to the team, but still, if he is capable, then they will be expected to show an astonishing performance before the end of the season.