how much camper can I carry

For the camper of which you describe, you’ll need a dually due to SRW (tire) weight limitations and for stability - Been there, done that, aint no free lunch $$…

3 tons

Method HD rims are about the only ones I know going up to 4k lbs per rim rating for LT size tires. If your rear axle is getting close to that 8k lb loaded weight,19.5 SRW rims are available up to 6k lb rating.

Jaycocreek is one of the few that understands the realities of pickup truck running gear… he’s exactly right.
The limit you’re up against is your rear tires and wheels.
You can step up to heavier duty/larger ones but there aren’t many choices unless you go to 19.5s.
Lately I’ve seen several big aftermarket pickup wheel rims, with the tires still on them, on the sides of the highway, busted out off of the wheel centers.

Your truck isn’t going to break, but the wheels and tires can under too much load.

We have a Adventurer 910 FBS carried on 99 F-350 Superduty SRW. Fully loaded worst case weights for us are 7600lbs on the rear axle and 4000lbs on the front.
Mods are upper/lower stableloads , 19.5 tires w/vision rims, rancho shocks and powerstop brakes.
We have airbags to but don't use them.
Truck/camper handles fine.

4000lbs + on the back of a 2007 short bed Ram 2500 for quite a few years, and 20k miles of hauling.
It was alot of camper for that truck, but the truck handled it fine. 3600-4000lbs tires depending what tires were on the truck. Home made stable loads, airbags and a sway bar. Not totally ideal, but worked well enough from WA to AK to WI and points in between.
I'd have no issue with what you're proposing. Just know that you'll have more body roll than a dually.
For the ultimate srw setup, add springs vs airbags and some 19.5s. I never did, because 300+ days a year that would have been totally overkill for the truck when not hauling the camper.

Your rear axle is most likely a Sterling 10.5 and the rating from the manufacturer is like 10K or close to it if memory serves me,so axle weight won't really effect your decision..It is way more than Fords stickers..

The Adventurer 89rbs is a fairly light weight slide camper if a slide is a must..Your truck will handle a fairly heavy camper but how comfy you will be driving it is another story...There top heavy and tippy in corners and make some people get rid of them fast because of the cornering....

A retired RV repair friend of mine bought a Eagle Cap 950 slide and put it on his newer SRW Dodge 3500 and took it home up a windy river road to his place near Elk City and sold it within a week because of the sway on the narrow road home...Said it needs a DRW because of instability in corners..

Good luck on your choice..