Howdy Tex,
So, a few things to think about.
1. The roof tents are only comfortable when on even ground, or after you have spent a bit of time leveling your ride (lots of options to do it but none of them are speedy)
2. Everyone that buys a rooftop tent should first do a camping trip where you set up your campsite and are unable to drive your vehicle. If you are that person then it's a great option, I found out that we are not even close to the kind of the family that could make one work. We camp far off the beating path and need vehicle able to drive to hospital on moment's notice if emergency happens, we also like to drive around and see other spots and do some off-roading and lastly occasionally we require more ice, or other provisions. These things are tedious because you have to collapse the tent, get sleeping pads out and deflated unless room in bed, secure it all down with awnings and ladder. It seems like the slightest of inconveniences but 2 trips in and switched over to pod tents and never looked back. The tents build in less than a minute, few more for lines and pack down takes even less time plus we maintain mobility. Keep in mind that if you do have to drive for any reason, you will have to do setup, including leveling vehicle and all that excitement all again.
3. With only using rack system you will need to be super aware of dynamic load limits. Rooftop tents are very light, and the force on hard braking can rip the whole thing off, so I'd definitely drill and install beefy or use a dynamic load calculator. Many people have experience with dynamic load sheer with roof racks and similar because of a lack of understanding dynamic vs static.
All in with the new tent, proper stakes and footprint it was something like $800 but the freedom we have again...priceless
I can't help but ask everyone I see with one how much they like their roof tent and almost always "it's awesome", then I point out the issues we had and then I hear "well yea, I wouldn't do it again, but we don't really use it that much" or some variation of that. I'm not saying they are a niche gimmick, but I really only see any practical application if doing caravan style overlanding.
Oh, and the tents are GREAT for the people that are afraid of bears and don't think they can traverse the modern miracle that is a ladder
If still loving the idea, I found this for ya and looks like it does what you want:
https://prinsu.com/product/ram-1500-bed-bars/