From what I get is that a charter school is a private school that gets public funding.
That is a silly notion. Just privatize all education. You don't need large campuses where you coral large groups of strangers into boxes for 50 mins listening to boring ass teacher, and then move on to another subject. There isn't enough time in each period to learn enough about topic to keep you interested. After the 24hr period you won't care to continue.
By privatizing, you can format any way you want. It can be five or so kids sitting in a nice park on a nice day. Or like ten kids sitting in a one room office with a chalk board. You can study which ever topic you want for as long as you feel like until you feel like moving on to someone else.
If you think you teacher sucks you can find a new one. And if these teachers suck, they don't eat, and their kids starve. If there are poor people who cannot afford on their own, we have something called welfare, sec 8, and food stamps that are already abused a lot, so they can get equivalent for education.
No need for public, charter, or even big large university campuses. Those places are just breeding grounds for liberals, SJWs, feminizes, pretentious yuppies, and phony hipsters.
Best thing though, is you won't get bullied. You don't have to be around kids you don't like. You can choose your class, and your mates, and your teacher. So no more school shooting.