I’d think about stiffer shocks. I put them on mine and it helped, Your rig should have front and rear sway bars. I’ve looked at Sumo springs and I’m not convinced that they do anything appreciable other than cost a lot, and the factory sway bars are pretty stout. Also a rear trac bar will probably do more than anything.
2016 Ventana 3427
2010 Bay Star 2901 1890w Solar, Leaf lithium bank, 3kw Victron “generator delete” system
“I kept the wine and threw the rose away....” Merle Haggard