If you are getting a PhD without a stipend (~3k usd/month) and even paying tuition on top of that, you are doing something egregiously wrong. The financial opportunity cost is very high though especially in CS.
I see online synchronous 1-2 hour exams as a mistaken result of the "let's emulate in-person teaching in a remote setting" mindset.
You don't succeed in remote teaching and learning by trying to make it as close as possible to the in-person setup. You have to treat it as an entirely different problem.
Consider the synchronous exam. It is a perfect method of grading in-person. It is hard to cheat and all people take the same test in the same place. It is as fair as it can get.
In an online setting however, people can face all sort of troubles in a few hour window in their home. Your internet might stop working, neighbor might be making too much noise etc. Everyone takes the exam in a different setting and it is as unequal as it can get. It is also practically impossible to prevent cheating.