yes tires make a huge effect on rolling resistance. An offroad tire drags a lot.

Get some slicks if you don't intend to go offroad. No need to change rims just don't try to put on tires that are too narrow for your existing rims.

No need to change chainrings ("sproket sa pedal"), just shift to a lower gear to make pedalling easier. That's what the shifter is for.

You might also want to change the suspension fork for something lighter.