My Ram is only 370/800 and I've never been in a situation where it felt lacking in power even when towing a 15k lb trailer. Our camper isn't even that heavy but I also have a gooseneck trailer I've loaded up to that level several times.
In comparing the big 3 diesels I don't think power has been a differentiating factor for quite a few years. They're all awesome from that standpoint.
Personally I think I'd buy a Duramax if I were buying a new 2022 and I'd give it the edge over the Cummins due to the transmission. PS would be third place. That said I'm happy with my 2015 and intend to keep it many more years.