To remove normal surface rust, hit it with a wire wheel which will get the rust off no problem. Then coat it with any satin black spray paint to cover the bare metal. Finally, apply Fluid Film liberally (I would say 4 times a year, even more if you want) and you'll never have to worry about rust anymore as long as you clean the underside after each time you drive it when they salt the roads.
It is a very messy job applying, you might want to check around for a service station that will fluid film your jeep and know how to get every nook and cranny.
Krown rust protect is also good but in Illinois the closest dealer might be ST Louis.
I like to avoid paying for services, but for something this messy I am will to pay someone with the proper application tools and a lift. They have long wands for areas a spray can will never reach like inside the frame. Your vehicle will drip for several day and you will see their oils penetrating the lap joints (like around the doors) where bad rust really start.
I agree with wire brush and paint but don't forget the primer! Paint cannot get everywhere so do what you can on a regular basis. Considering the pictures are of a 2017 Jeep, you live in the rust belt. Realistically you cannot wash every time that you drive in salt but do what you can. Some people like to use a garden sprinkler under the jeep to gently flush away the salt residue. I have heard rumors of car washes reusing water (after questionable filter), so who knows what we are getting there. I use these blackforktool.com to help keep the inside of the frame clean. Jeep left very large hardware access holes in vulnerable places. Golf balls could literally enter your frame without an exit path. And finally your best friend.........Fluid Film! It really helps! I have seen it for $100/car or $150/truck. If you do it yourself you could do the frame inside also.