As far as campers go, all I have ever owned is single axle trailers except for a small toyhauler trailer that I owned for 2 years that was dual axle. I had a little 1975 Apache pop-up for 8 years that towed fine as a single axle trailer. Course that thing was heavier than most average pop ups as it was all fiberglass instead of canvas still it was rather light and it towed like a dream behind a 4cyl S10 no problem and no weight distribution hitch of any kind was needed as tongue weight was so light.
I then moved up to a 17' 1968 tag-long traditional hard side box type camper that was single axle . The tag along was heavy but towed fine behind a full size half ton C1500 with a little V6 no problem at all - and no weight distribution hitch needed.
In the early 1990's I moved up to a 1975 19' single axle hi-Lo hard sided trailer and I am going on 30 years camping with this trailer. It is a heavy trailer for what it is as all the wall studs are all made from steel box tubing. It tows fine with a weight distribution hitch behind a 1/2 ton truck but it is awful to tow without a weight distribution hitch as the tongue weight is steep. I wish it was a double axle, but I picked it up cheap and it has worked just fine for me for 30 years and I plan to use it another 10 years yet as well.
I had a near new 20 foot small toyhauler that was dual axle that towed fine without a weight distribution hitch. Kept it 2 years and sold it went back to the ancient hi lo trailer
I do own two double axle heavy duty type trailers. One is a dump trailer and the other is a flat bed heavy equipment trailer. These both tow fine without weight distribution hitches even on 1/2 ton trucks. Double axle trailers do tire scrub though where a single axle trailer never will tire scrub so in my opinion that is the only advantage of a single axle trailer. The single axle camper is also slightly easier to level up on rough terrain as it is simple to put a 2x6 down on a block of wood and run the low side tire up the ramp to make it level quick and easy. This hillbilly method of leveling is possible but harder to do on a dual axle trailer. That said, I will take the double axle everytime.