I think Kelce has lost a step. Also, their OL is not good. It is all on Mahomes to make plays happen. The coaching looks awful too. Maybe part of why they are losing is because instead of working on fundamentals, they spent practice time installing a bullshit play that revolved around Kelce taking the snap and doing a behind the back lateral to Mahomes. Great use of practice time there.
If Kelce has lost a step then you just take away Hill. Sure he's good but you can take away any player if he's the only real option. They don't have a reliable #2 WR.