As others have mentioned I'd start with tire pressures when empty, do something about the front swaybar unless you have a high center of gravity situation (regularly loaded heavy above the bed rails like an in bed camper for an example type of high center of gravity load), and then any sort of springs/shocks would be the cherry on top.
For the rear you can look into different shackles even if you don't want to change the leaf springs. Different shackles will help take some of the bite/jarring out of the ass end - I've ridden in plenty of trucks that have sulastic shackles that seem to work well and there are also options from Thuren and Carli.
Since you mentioned you don't want to lift it I'd imagine you also don't want to break the bank (Could be wrong here) so I'd probably look at doing the following in this order -
1.) Thuren Front Sway Bar - By itself this really does help the front end feeling when going over uneven surfaces, hitting drive way entrances at an angle, speed bumps, etc.
2.) Front .5" Thuren Springs and Shocks - I'd go with the 5100's Thuren specs for their front springs unless you really want to spend money, however, IMO I would go 5100 or straight to big boy shocks like King 2.5's. The Fox 2.0s aren't worth it over 5100's IMO and I'll be replacing mine with either King 2.5's or the Carli E-Venture shocks when my Fox 2.0s are ready for a rebuild.
3.) Rear Shackles + Shocks - I would look at Sulastic, Carli, and Thuren's rear shackle options along with getting the matching rear shocks to whatever you get upfront. While I haven't ridden in many Ram with Sulastic shackles, I have ridden in plenty of mostly stock F350/F450s that have em and I feel they were worth it for what they did to the ride compared to a truck without them IMO.
4.) Front Sumo Springs - With only .5" lift springs I would likely look at the blue ones and would only run black sumos if you are sticking with the stock front springs or lifting in the ~2"+ range. I feel my black sumos engage when I hit larger bumps, whoops, etc and while they're not too jarring when I expect to hit them I wouldn't want to deal with them engaging regularly if I had less lift.
5.) Thuren Rear Springs - If max payload isn't a concern or you do plan to add bags then Thuren also makes rear progressive leaf packs that only raise the rear .5" (Thier shackle has a .5" lowering hole so combining the two you can keep the rear stock height if you didn't want to raise the ass end any).
6.) Radius Arms - I like configuring the Metal Cloak Radius Arms into the two piece configuration WITHOUT the lock-n-load. They free up the front axle to articulate when combined with longer travel/softer springs like the Thuren springs. The bushings also don't bind up, allow for free movement when needed, and soak up smaller movements due to the bushing design. Going through rough construction zones, over curbs at angles, and playing off road they are the cherry on-top for my build. So much so that I'm very much looking forward to ordering the Thuren rear control arm setup for the 2500 assuming my anual bonus doesn't suck so I can correct the rear geometry and get rid of the bushing bind I can very much feel in the rear compared to the front.
