For a mainstream example, take Fast X. It's an objectively stupid movie with a great audience score - because it's exactly what it says on the tin! Nobody is confused about what they're watching. Nobody thinks they're going to get terrific drama or romance or suspense. They're going to get the 9th sequel to a comedy action movie about dudes driving cars.
Blue Beetle: 78% critics, 92% audience
Gran Turismo: 63%, 98%
Elemental: 74%, 93%
Meg 2: 29% 73%
Haunted Mansion 38%, 84%
Indiana Jones: 69%, 88%
Little Mermaid 67%, 94%
Those audience scores are not "more accurate" in any way. People who are forced to see these movies like them less than people who chose to see it.
There also really isn't anything currently that fits into "the political correctness / marketing budget of the movie" claim of OP. It seems like they are just buying into cultural war nonsense. The closest I can find is Barbie and its critic score is 5% higher than the audience score, so not much of a gap.
My favourite way of judging movie quality is checking what kind of movie goers hate it and why.
You rate movies. The consensus ratings you see are based on people who have rated movies similarly to you overall.
High Audience Score: HA High Critics Score: HC
HA + HC: Great movie to watch
HA + no HC: An entertainment movie but don’t expect a masterpiece
No HA + HC: Avoid unless you have obscure tastes or if you are pretentious
No HA + No HC: Probably garbage
At a high level what I really want is two ratings: Global rating and does this deliver what it promised. A greasy spoon is objectively not a good restaurant but it scratches an itch and you have certain relatively low expectations of it so in the context of greasy spoons generally I might rate the restaurant 5 stars even if globally I'd give it two stars.
As you say with Fast X: objectively it is not a good movie but it absolutely delivers what it promised. People who like that movie series will be pleased with it so in that context it deserves a positive rating.
As a follow-on I want to tell the system about the things I like + the things I hate. Then I want the system to give more weight to ratings from others who both like and hate the same things. I honestly don't care if critics or audiences liked the movie... I want to know if people who in some way think like me enjoyed it.
-Pretentious watchers hating on summer blockbuster movies
-Political things and review bombs
About your specific example Steam comes to mind, they have a great review timeline feature that allows to filter out review bombs.
One feature that would be nice would be a filter to filter out reviewers based on certain criteria
-only one review
-only has reviews on certain films
-account life is less than specific threshold
That DB query is probably too expensive to run on a free site though. An app that scrapes the RT reviews and filters out based on this criteria has been on my list of things to build.