So I have a used 2016 Genesis 3.8 sedan since last year, and a really happy with. Recently decided to replace the front brake pads, did the left wheel no problem, easy peasy.
But when trying to take off the right wheel, turns out, one of the wheel studs is loose in the hub, so when you turn the lug nut, instead of unscrewing, it just turns the stud, and I cant get the wheel off...

Suggestions ?

 

This is what I would do,
Get a good drill, drill a few holes starting with a small bit and working up to a larger bit, into the center of the stud using a pair of vise grips to hold the nut. Eventually you will be able to break off the nut and remove the wheel.
If the stud is loose enough you might be able to hold the stud and turn the nut off. As it gets looser it might come off easily all the way.
Once off carefully check the wheel hub for possibly getting messed up at the hole the stud fits in. If that has happened you will need to replace the hub assy.
There are a bunch of methods you might try , another is if you can cut a slot in the stud , with a cut-off tool then hold it with a screwdriver and remove the nut.
You might be able to get your hands on a nut splitter and if there is enough room use that tool to split the nut and remove it.
Don't even think about using the vehicle with one stud missing, not smart !