Well if the RT score for eternals goes below 50% then you could say most critics do not like.This, like I get defending the movie but some MCU fans will say anything no matter how non-sensical.
It's critics who don't like it, critics who rated it the worst marvel movie ratings wise.
Anyway it's not worst marvel rated movie,but it's the worst rated mcu marvel movie from critics.
We have to see the audience RT score as well and cinema score.