My Dakota has:
https://rollnlock.com/m-series
Not this exact one, a different brand probably bought by this company as it looks identical. Also it was bought in 1998 by the original owner, so I do not know if anyone makes something exactly like this for a Ram anymore.
There are other similar products out there. Some fold up, etc. Mine is a soft vinyl over an aluminum cover. Like one of those roll up garage doors, 1" square sections that are all hinged. So it is really quite strong on the surface, and when it is rolled up all the way it is totally out of the way. It locks, but 90's truck tailgates don't lol so there is that.
I made a brace to go across behind the wheel wells to keep stuff from getting too far in so I can reach it from the tailgate. Works for most things, easy to take out if I need to.
This would cover you for everything except the camping out, unless you are REALLY OK with scooting up in there!
I have had caps on most trucks I have owned, going back to '79 farm truck and the impossible to see through the "windows" aluminum cap, to a black fiberglass 80's job with tiny side windows, to a "modern" color matched Eagle fiberglass on a 90's truck. First two had bare beds, last one had the plastic ribbed KNEE DESTROYING bedliner, the type that everything slides around on no matter what lol.
My current tow rig has no cap, but I do want one. Whole bed inside and under was sprayed with Line-X, so no plastic liner. For the odd time I need to move something very big, I can put it on my trailer. It is so handy having an enclosed space for weather and security, and modern designs do not affect visibility like the old ones from decades back did. They make caps specifically designed for camping, but otherwise you can get them with carpeted interiors and if you are serious about camping out you could get a Bed Rug(the brand, not a remnant from the hardware store) which would make it pretty cozy in there.
I don;t live in town, so silly things like "time to get gas for the mower" means without a cap I have to put empty gas cans either in the cab or trust they will not fly away as I have to go a mile up the road(55mph). With a cap, open the rear window, drop them in, leave. It's like that for everything. Tie down a sheet of plywood, or close the gate/window? all the odd jobs are easier and more secure when you take wind out of the equation. And rain. AND SNOW.
But if you constantly find things you have to climb up into the bed to load or unload a cap will be a pita. The roll up like my Dakota has would be much better in that regard.