I think that the transfer method that Chelsea is doing is more on young players who will not play in the Premier league, but some of the transfer players will enter the first team and now there is still a chance for Osimhen to join Chelsea this can add strength to them, it's just still skeptical what Chelsea will do later.
Poch in the last season did a good job where Chelsea won in a row which ended up in 6th place could shift Man United, but now Maresca comes as a new coach this will be difficult again to adjust.
If Chelsea focuses on building up their team with young player, it's a good and sustainable strategy. They are rich and can buy one or some star players to support young players and make a very competitive team. After about 2 decades of spending huge money for transfer and salary, and gaining some success with two Champions League and several Premier League titles, I believe that Chelsea already understood that this is an expensive strategy but not sustainable.
By focusing on and growing up young players, Chelsea will have a very good player resource to use with cheaper investment cost and can have a long future with these young players. Having a good youth academy will be another great foundation for their club success and a more healthier finance.