Most companies that manufacture truck campers recommend some type of suspension upgrade - such as upgraded leaf springs or an air spring/air bag kit for the rear suspension. I went with an air spring kit from Air Lift and these have been my results so far.

I am not an affiliate of Air Lift, but here is a link to their website if you want to read more about their products.

https://www.airliftcompany.com/

And if you are interested in a portable air compressor, head over to Amazon or your favorite car supply store. There are a lot to choose from. As you can see in the video, my model pre-dates Amazon, but here is a link to a similar product that plugs into your car outlet. (I am an Amazon affiliate and may earn from qualifying purchases.)

Portable Air Compressor: https://amzn.to/3y7bziF