In my experience people who are permitted flexible work schedules and take advantage of them tend to be the better employees.
Mostly don't you sit down with your team and figure out good meeting times and bad meeting times? Did employee say 11am is a great time for meetings then go get an 11am hobby? Then sure employee is a jackass.
Any coding, debugging, thinking had to be done either after 6pm or on weekends, or WFH. Now perhaps you can see why people coast; not everybody is willing to sacrifice nights and weekends to be productive.
That's where the demands should lie, not on "bottoms on seats"
Most don't advertise this widely, for obvious reasons, but you see it mentioned occasionally in places like HN, or tech-focused subreddits.