Hello @Vesna10,
You can always message a guest who leaves an overall review of fewer than 5 stars to ask what the issue was. I've done this in the past. Some have answered so I was able to take action on what they mentioned. I made the decision to ignore one suggestion as it was not in my style of living or hosting and only one guest had mentioned it. In each case they had given a glowing written review and 5 stars on each category except "overall", yet they kept the reason secret until I messaged them to ask.
So, no, we can't trust guests to address an issue verbally to us. They will hide behind the rating system and deduct points even though they've smiled forever and told us when talking and messaging that everything was great.
https://www.airbnb.com/help/article/1257
While people can disagree about what rating a particular issue should come under, Airbnb does offer the overall one as a completely separate rating as not all possible issues can be shoehorned into the limited list of other ratings. Yes, I agree it does seem to be the case that more importance is attached to it than to the sum of the other ratings, as mentioned in the article below. You're very forgiving when you say that the host entering your room unanounced is a communication issue. What about feelings of safety and security?
https://www.airbnb.com/help/article/1303
As you left a review when you travelled this year and you don't agree that it should be a separate rating, take it up with Airbnb as they're the only ones who can do anything about it. As the "Host voice" system seems to now be discontinued you can do it via the "feedback" process.
https://www.airbnb.com/help/feedback
Steve.