Depends on the definition of luxury.
Enterprise does have what they call their Exotic car rental business and they have a location in Etobicoke just outside the airport.
Standard stuff, BMW , Merc, Tesla, Cadillac, Maserati, Porsche, Range Rover etc etc.
I have used them a few times when I have needed a behemoth like an Escalade or Navigator, they provide standard large biz good service.
If you are looking to rent long-term however, they may not be your best bet due to the high cost.
There are probably a ton of smaller shops that would be happy to rent you a nice car for a month or a service like Turo could be a great fit.