I've had some 4 stars ratings for individual items like "value", but apparently, as long as 3 out of the 5 are 5 stars, you'll get a 5 star rating from that guest. So, two 4 stars and three five stars equal a 5 star review. But once you get one single 4 star overall review, yeah it's maybe impossible to get to a perfect 5.0.
Look at reviews of hotels. It's impossible to operate a hotel without a 1 star yelp review. People understand this, so I wouldn't worry about having a less than perfect rating.
There's an Extended Stay America in Woodland Hills, CA that has a collective 1 and a half star rating! But people just keep on booking nights there like there's no tomorrow, although under coronavirus I'll bet the place has been bought out by the city and turned into a permanent homeless shelter by now.