I don't have any data to corroborate your presumption (or maybe conspiracy?). From my observance, most of the films that are of quality get positive reviews and most of the films that are not good get bad reviews. RT is a movie review aggregator, their score is specifically more like approval rating, not an indication of their quality rating.
Final Reckoning has 80% approval rating, meaning 80% of the critics found the movie to be positive but their quality rating varies. Take my review and some of the posters' reviews in here. I didn't love the movie, there are several things I didn't like about it, but I still gave it a passing score.
But if you have specific examples of movies post COVID that you feel that don't deserve their positive reviews, list them and we'll take a look at it.