I give my kids 30 min "free" on Saturdays, which gets doubled if they spend it in a game with a sibling. For trips, I make my kids all do the same thing, so either watch the same show, listen to the same audiobook, etc.

I personally don't digitally track what my kids do at all, I instead rely on trust and keeping devices in a public space. I tell them what's acceptable, and occasionally hang out with them while they're doing whatever. As they follow the rules, I give them more autonomy (e.g. my oldest may get their own PC soon-ish), but if they break the rules, they lose access. The only parental controls I use is for my 4yo, because she keeps getting into my Steam Deck and Switch w/o asking, but my other kids know the passcode on the Switch (not my Steam Deck, that's mine).

It's a bit bumpy, but I'm hopeful that having rules but no actual walls teaches them to learn to self-regulate and will help them in the long-run. It worked for me as a kid.