It shows the character of the person. Pre-Covid, I would open the door for my partner, and if there were people behind us I would hold it for them.
One time there was a set of three people blocking the door, woman, two teenagers, and they were waiting for the man, a black couple and ourself.
My partner was pissed she bulled through (she is a redhead :). I went to support and I opened the door.
The teenage boy look perturbed because it made him stop looking at his phone. I opened the door for her, and said, hey why not go in there is plenty of space and held the door open.
They went in and the supposed husband came rushing up and went in before his partner. Then the black couple stood there. I was like "coming?"
Look of shock, I said it wouldn't be nice to slam the door on you or make you wait. They smiled and went in.
Chivalry has a place and it doesn't know gender, and as you state correctly ... it is all about manners.
So few people have it, so many need it "badly".