as Boris says – the screws are just to set the end points (max and min). There is also the b-screw which sets the clearance of the derailleur from the cassette sprockets.
Max should be set so you can’t push the chain off into the drop out. Min should be set so you cannot push the chain off into the spokes.
In between that there is no effect and that is done with the barrel adjuster.
if you are experiencing chain suck – ie the chain getting jammed up between the chainring on the crank and the frame then it is often a case of bad shifting but also a sign of worn or just dirty components.
check the wear on your chain (look up chain measuring instructions) and also look for any shark fin shaped teeth.