Dynasty/Keeper Hybrid : Big Trade, Need Advice

Dynasty/Keeper league PPR, 6PT passing TD, big trade offer.

Current Roster:
QBs : Winston, Josh Allen
RBs: Barkley, Mixon, Kerryon, Drake, Gore, Gallman, Darrel Williams
WRs: Godwin, Boyd, Fuller, Marvin Jones, Dorsett, Demarcus Robinson
TEs: Kelce, Kittle

Keeper yrs is 20 tenure years.
Keepers for next year if no trade:
Kittle (3), Kelce (4), Barkley (2), Kerryon (2), Mixon (3), Godwin (3) and Boyd (2).

Trade is: Mahomes, Diggs, Dede Westbrook, OJ Howard for Winston, Mixon, Kittle, Boyd.
Mahomes owner is down with the above trade. I have asked swapping out Westbrook with James White but waiting on response.

I have build my team over the years to have a strong starting lineup; Kittle and Mixon are usually my flexes. Westbrook and Howard are throwaways in that trade. Is the upgrade in Mahomes worth sacrificing my starting lineup depth? Keeper league makes Mahomes very interesting but I’m giving up 3 strong players from my starting lineup. I do get Diggs whose situation could improve after this season.

Any advice is highly appreciated.