Chelsea need to be much more active in the transfer market now. They even need to be the most active team among the top teams of the league. Because they have parted ways with many players in this transfer window. They will need to replace them with solid alternatives as soon as possible. They are in a rebuilding process in short.
Pochettino has a big responsibility to carry this team to the place where they need to be. Chelsea wouldn't target the league title for now of course. The first step will be to finish a season in top 4. They still need time to be able to fight for bigger goals after leaving a poor season behind.
Chelsea is selling players to make sure the roster is flawless for the upcoming season, but my advise to Chelsea is to check everything out thoroughly to avoid making any mistakes by selling a player they'll later regret. The squad should only concentrate on being in a better position so they can perform in the champions league; it will be beneficial if Chelsea doesn't compete for any titles next season.
Although selling players can help the team, and I think Chelsea has many players they can offload while still having money left over to invest in new, talented players, I would also advise Chelsea to replace the sold players with new ones who are capable of playing at a high level more than those who will compete in the 2022–2023 season.
So far for the blues, they've successfully let go of players that should leave, though, Kovacic I didn't see leaving, Kai Harvertz likewise, bit I'm not sad over the push out of Koulibaly, Loftus Cheek, Ziyech, as for Ngolo Kante and Mason Mount they do deserve to extend contracts with the club, but Pochetino does have his own plans. Hopefully selling all these players doesn't backfires.
More players are still likely to leave the club, Azpiliueta is another, But they honestly need to consider the purchase of Victor Oshime from Napoli. They need goals c'mon.