are game developers paid fairly?

Sounds like a difficult thesis. I'm fairly surprised any thesis advisors advised you to go forward with it, as that's something even people in management and payroll systems are reluctant to tackle, and they've got access to hard data rather than surveys.

"Fair" is always going to be subjective. There are certainly tech companies that pay far higher wages than the game industry. On the flip side, relative to national averages and broad cross-industry jobs, game development jobs tend to pay quite well versus many other industries. It depends tremendously on what other mix of jobs are being used in comparison.

"Fair" needs more definition.

Is it "fair" that FinTech or FAANG / MAMAA / etc pays a tremendous amount of money, but that logging workers, one of the jobs with the highest fatality rates and a tremendous number of workers who lose fingers and hands, are generally paid relatively little? Similarly with roofers and construction workers, relatively they're quite dangerous jobs, about half as deadly per capita as logging workers, but still among the most dangerous jobs out there, is that "fair"?

Is it "fair" that people might get assigned randomly to teams; two people hired by a large AAA studio with roughly equivalent skill sets, one assigned to project A and one assigned to project B. Through no decision nor fault of their own, project A finishes early, gets accolades, and everybody gets a big bonus, where project B becomes a death march, is cancelled, and half the team laid off?

Location also matters. Is it fair that two people doing the same job but in different parts of the world are paid different wages? Is it fair that a worker in San Francisco, New York City, Hong Kong, or London is paid so much more than a worker in Dakar, Quito, Perth, or Hanoi?

You write about negotiating pay and choosing between companies, but I don't think that's realistic. Prospective employees have extremely little insight to the companies they're applying for, they can see the public face and they can see the limited amount they're shown in an interview, but the interview teams tend to paint a rosy picture and don't typically expose candidates to the dark sides of the companies or the business risks they're facing until after the person is hired. Similarly for salary negotiation, the potential employee has no way to know with any certainty what salary ranges the company is potentially willing to offer, neither the upper nor lower bounds. Through some skilled negotiation and being mindful during interviews a candidate might discover the company has a very high need for their skill set and would be more likely to pay more, they still don't have a way to know the full range the company would be willing to negotiate. There are a tremendous number of job hunting books and salary negotiation books, some focused on employees to negotiate the maximum amount, sometimes even more than the company was considering offering, and for companies to limit the payment and keep costs down. And then with even more complexity, the composition of the team and the number of people being hired at the same time matter, the money the company happens to be bringing in as income at the time matters, and higher pay makes a person more likely to be terminated in layoffs when money is tight.

As for your survey, from the progress bar getting about 1/3 through and after a bunch of intrusive questions I tried to answer ambiguously, I gave up on it.