Volvo ex30 is the cheap electric volvo and is about to come out. The Polestar cars are usually more "sporty". Polestar used to be Volvo's equivalent of "amg", their sport division. Then Geely(the chinese owners), spinned it into its own brand, though obviously there are a lot of similarities between Volvo and Polestar.
Polestars arent fancier or more luxurious or even more expensive than Volvo cars. Polestar 1 was experimental and pretty expensive but polestar 2 starts at below 50k €. Polestar 3 will be their SUV, which starts from 80k+ €. Volvo ex90 will start at 90k+, though it is a full size SUV, while the Polestar 3 is mid size crossover.
True. Volvo itself is fairly fancy ... At least they have a lot of the nicer, more luxurious models. I just sort of think of them like I listed since they're more rare.