2013 Santa Fe, back tires are wearing

Need more information. "Tires don't look that bad" is not quantitative. Accurately describe the tire wear in inches or mm, inside to outside, right and left. Or post photos at a photo upload site along with accurate description of each.

Won't help. Once the tires start to wear unevenly it does not stop just by aligning. Meantime, you can hit a couple of potholes or curbs and knock them out again before you finally do get the new tires.

I can't tell if they are still good or need to be replaced without seeing them first hand. Ay 40,000 miles they should be fairly worn though. Only way to be sure is to measure the tread depth in a few places. Unless you are in a snow free place, you want good tires with plenty of tread for thr winter.

If you plan on keeping the car for awhile, it pays to just get new tires. Some things are not worth fooling around with, or risking life and limb over. If it were me, I'd be replacing all four tires now, even if they don't need immediate replacement...they all will soon.