Yes you are right, but the people that can fix a match are probably those in higher ground like VAR, is just like the match are on the hands of this guys, they can easily cancel any goals that's scored by those they do not want them to win. However it is bad to fix a game and mostly when they fix the game in a way that the strong team have to lose.
I doubt if the VAR could risk their job to that extent only to get match fixed, for them to be employed to do a professional service, they are expected to to condole any form of corrupt practice and if found, they are going to risk loosing their job, which i believe the consequence aftermath will be more higher than what they tend to be rewarded for fixing a match, maybe other people are doing such anyways aside the VAR.