Everything you do with this vehicle is going to lower its value. Every mile you put on it, everyday it sits unused in the driveway lowers it’s value. But you bought it for your own use, not someone else’s, so use it the way you want to.
There are bike racks that attach to the back of the vehicle without a trailer hitch. I had one of those, the problem is that you are far more likely to scratch the paint with your bike, that will lower the value a lot more than a trailer hitch.
I also have a 1.25" receiver on my small pickup. It is perfectly adequate for my trailer, however, if I were to do it again, I would get a 2" receiver, you just have more options with it. I needed to tow my son’s Tercel Wagon across town one time but U-Haul would not rent me a tow dolly because it wasn’t a 2" receiver.
If you want a platform type bike rack, I think it requires a class 3 or 4, 2" receiver. I believe it needs to have a tongue rating of 500 lbs. Even though your bikes don’t weigh anywhere near that much, they do have a mechanical advantage on the receiver because their center of gravity is further out.