Sorry, I’m confused… is he urinating in the same corner, or a different corner? Is this all happening in the box, and he’s just urinating off the side of his litterbox instead of in it?

Move his box to where he has been peeing, he seems to prefer that area more for some reason :p Put his poopies int he box and some hay so he will sit in it like a good boy

Welcome here! This is very frustrating! He may just need to be retrained from scratch. Can you try to limit his freedom and then slowly increase his area? Is the area rug the ONLY place he is urinating outside of the box? Have you tried to remove the area rug altogether? Once that smell gets in there, it’s very hard to clean.

Have you had him checked for a urinary tract infection?

I wasn’t sure when I read your post what you meant by “that corner.”  If it is the same corner, but it is somehow spraying over the litter box area, then a corner litter box with high edges would be useful.  But if it is a different corner, your bun probably just found a new spot to go to the bathroom in.  Once a bun chooses a spot, they stick to it.  Thumper changed her spot after furniture was moved around and she was spayed, in fact she was even peeing in her brand new basket of hay!  It’s a lot easier for a bunny to poo in a new spot than it is to pee, so move the litter box to that spot or get another box to put in that spot if you can.

When he comes out the cage and goes to the box, does he actually pee then or just goes to it to claim it or hang out? Then he goes back to that area after but pees on rug instead?
You could try moving box to where he’s peeing.
Main reasons for sudden change are:
Health reasons
Change of litter
Box too clean or too dirty
New animal or person in household
Box too small
Negative association with litter box – ie, received a fright while in it one time.
There’s probably others I’ve forgotten. Does he have a box in his cage too?