Trade M.Sanders and Chark for Hill and Bell?

Full PPR.
I have Jacobs, Sander, Hunt and Mostert as RB and Cooper, Chark, Crowder, and Deebo as WR

I probably wouldn’t. Your RBs are strong, and I’d probably keep it that way.

yeah thats the strategy I started with and its working out pretty well – I am just worried chark may never be a WR1 and this might be a good opportunity to get Tyreek cheap

I wouldn’t. Personally not a fan of hill because he is so boom bust for a wr1. Cooper is doing pretty well despite not reaching the end zone yet this season, he’s 1 td away from being a WR1, and sanders is worth a lot more than bell.