Most the bad teams i see can’t possess anywhere near 35 seconds without turning it over anyway so not sure that will help.
Try this to increase participation:
(1) limit open gym and summer contact with coaches. High school sports shouldn’t be de facto year round.
(2) no contact with student athletes during a two week Christmas break period.
(3) shorten the season a couple of weeks;
(4) better scheduling by ad’s. Heck let some teams play both a jV schedule and a varsity schedule depending on strength of opponent.
I'm not sure about #2. Winter sports are in season. Maybe limit practices or something.