Improvement can be made nonetheless, like on those aspects you mentioned. New signings would be most welcome but it shouldn't be seen as the solution to our problems. Moreover, Lampard reportedly talked about a 3-year plan to challenge for the Premier League and Champions League (latter might be asking a lot in 3 years but that's another debate) when trying to convince Ziyech and Werner to join us. So next season is year 2 and assuming Lampard has planned out what to do, then yeah, he needs to improve the side through coaching, new signings or not.