To address your other question
What if the white dwarf was orbiting a supermassive star(not giant
An interesting fact about main sequence stars is that the more massive the star, the lower the star's surface gravity, so the more massive you make the star, the more easily a smaller companion star, not necessarily a white dwarf but any smaller and close companion star, can draw matter away from it.
Sirius for example, is a little over twice the mass of our sun, but 1.7 times our sun's diameter. That means it's surface gravity is 2/(1.7^2) or about 70% of our sun. It's counterintuitive but largely true that the more massive a star during it's main sequence, the lower it's surface gravity. It's also true that stars like our sun grow larger over time even as it loses mass, so the age of the star matters too, but generally, more massive stars have lower surface gravity.
Trappist 1, a red dwarf star is about 1/11th the mass of the Sun and a bit under 1/8th the diameter of our Sun. That gives it a surface gravity of about 6 times our Sun's surface gravity.
That's why there's a theoretical limit of how large stars can get, somewhere around 150 times the mass of our Sun. Around or a bit above that mass, the internal heat and outward pressure from fusion pushes the outer edges to the point where the outer layers of the star are hot enough and loosely held enough by gravity that they can escape the gravitational field of the star.