Chelsea already has a large number of new players, therefore adding more players is not necessary given the quality of the players they already have on the squad.
Chelsea needs a new coach, as you have already indicated. Although fans have been calling for a new coach for a while now, I still don't understand why they haven't yet followed that.
By the start of next season, am anticipating that all of Chelsea's new players will align with one another on the field of play. By then matches will be won
Chelsea usually have better performance after sacking a coach but this season is different, their coach is safe but they bought many new players who have yet adapted to their club. Their performance has yet been improved after the winter transfer season and worse, it looks to be worse and more decreasing in latest weeks.
A few weeks ago, Chelsea and Liverpool were at similar situations and they stood closely on the table with two consecutive rankings. However now Liverpool are moving closely to top four and have very good chance to join top four. In contrast we can say Chelsea already lost their chance to participate in top four in this season.
Chelsea are not a counter attacking team they are a attacking team that has the most possession of the ball. Dean Potter has turned them into a counter attacking team but the players are not setup correctly to counter attack because they are not used to doing it. Dean Potter should have played attacking football like Chelsea did before he took over and then change the tactics in the pre season for next year because he would have more time to develop a system and allow the players to adapt at the moment they are trying to adapt in the middle of a season and every time they lose a game because they are trying to adapt they lose confidence.
Chelsea owners from Abramovich to current owner want to see sexy football in Chelsea but in their history, in the past two years, it's barely to see sexy football in Stamford Bridge.
Potter did built up a good pressing tactic for Brighton that brought him to Chelsea and it's strange to see what he is doing in Chelsea. Maybe he changed himself to pressing to defensive priority because in Chelsea, he has to face with bigger pressure and with many bad results, he lost confidence on himself and his favorite tactics.
Chelsea were a defensive team under Mourinho but Tuchel tried to change that into a attacking team and it worked for a long time before he was fired but since Dean Potter has not improved by going more defensive and trying to counter attack.
Tuchel is more flexible than Mourinho in tactics and he is more friendly with players than Mourinho. I consider Tuchel is similar to Carlo Ancelotti who don't mind much about ego of players. They are coaches want to maximize results for their clubs and different than Mourinho who want to achieve best results but still don't want to fail in internal fighting with star players.