Plenty of threads here to indicate 35x12.5 are probably going to rub the radius arms @ full lock on stock wheels.
Looks like 20" offset is +55. 18" offset +20
You need to specify the trim/wheel if you want a solid answer.
Most go with a +18 offset wheel for 35x12.5 to 37" tires. That's going to move the inner wheel lip out 30mm or more depending on your stock wheel.
35" will fit all day long with no lift or trimming, just need to push them out a little if you go wide.
37" will fit that +18 offset as well without a lift but require lots of trimming and shaving down the pinch weld at the rear inner fender. They will rub at full lock.
Use the advanced search at the top of page for best results. I used "stock offset" and got this thread hit.
Have a new 2021 2500 Tradesman with the 18" wheels. Intended to get a set of black aftermarket wheels, for appearance and lighter weight, but have been frustrated by the fact that virtually all budget off the shelf aftermarket wheels have a significantly smaller positive offset vs stock, most...
hdrams.com
Google fu also works.
This might be accurate for stock wheels though I know of no 22" wheel opffering
Ram 3500 2021 - Find out the correct alloy wheel fitment, PCD, offset and such specs as bolt pattern, thread size(THD), center bore(CB) for Ram 3500 2021
www.wheel-size.com
This should help calculate suspension clearance (check stock full lock clearance).
Tire Tech Information - The Wheel Fitment, Tyre Stretch, Rolling Radius and Speedometer Error Calculator. Play with specs, try different settings, compare results
www.wheel-size.com