Firstly, no you can not just fit different wheels.
Second, you are obviously having a problem with the RWS system which we might be able to help you sort out.
If you want to bypass the RWS system then you will need to replace the transmission & wheels as the "normal" one has longer axles
or
Replace the axels & wheels if you want to split the tranny
or
Weld the universal joint so it can not bend
Not sure about your exact model but a customer with a Husqvarna 4WS, made by Noma ( who went bust ) ended up welding the uni joints solid 2 seasons ago.