I have heard of some cases for it happening in video game journalism, but it's relatively few cases, and game journalists are usually on smaller sites, and it's a smaller industry. I don't know how many more movie reviewers are out there compared to video game reviewers, but it's probably a lot, and a lot of them have homes at pretty big and established publications. Even if a couple of people were bribed, it would be impossible to do on a large enough scale, and if somebody told, the studio and anybody who did accept would be toasted, so I assume the risk wouldn't be worth it unless the bribe is ridiculously big. It's all pretty hypothetical, at the end of the day, if reviewers [I]had/I] been bribed to say, like TLJ on a massive scale, why is Rise of Skywalker getting less good reviews, Bob the accountant forgot to send the checks?
And the other bit, that's a fair opinion, I'm just not one of the ones who agree with that assessment.