I don't plan on having a pickup with a gas motor ever again. I have had GMC pickups with diesel motors since 1994. Started with a 1/2 ton with the 6.5 Turbo diesel, then the 6.6 in a 2500HD in 2003 and 2008. Currently have a 2017 2500HD and a 2024 3500HD, both with the 6.6 Duramax and Allison transmission. There are higher routine maintenance costs but not that much more, 10 quarts of oil for the Duramax vs 6 for a gas motor. Other than that, everything else is pretty much the same, oil filter, air filter, and fuel filter. Major repairs can cost more if you have to replace an injector pump or injectors.
Our needs have changed somewhat in that we need an enclosed vehicle to transport large stained-glass projects, 3'X4'. I plan on trading in the 2017 2500HHD on a new Yukon 4X4 with the 3.0 Duramax.