National has pretty flexible status match program. you should be able to match five star to executive. https://status.emeraldclub.com/
If you are looking for an EV, then go with Hertz since they have the largest EV fleet at YYZ (Model 3/Y & Polestar 2)

And charging for tesla is easy, just refer to Hertz tesla page, you don't need to sign up for anything and Hertz will pass the bill to you.