Chelsea's sale was not effective in my opinion, a lot of their players left for cheap and they also let go of a lot of key players so it is necessary for them to be able to find a suitable replacement, it will cost a lot.
Chelsea made a major team overhaul and that made it a little risky to build a team from scratch again by replacing all the important pillars, but if you look at what they got, this had to be done and cost a lot in this transfer market.
I think the most important thing is that they were able to get clubs interested to buy these players because without the sales, it will be difficult making further recruitments and the wage burden of the club will increase rather than decrease. This is good development for the club whether they sold their players for the right price or not, at least they created space for incomings.