I've build some moderately sophisticated server systems up on "bare metal" (as the kids say), know my way around a shell better than most programmers, understand networking better than most programmers, et c., and I still find restricting and monitoring kids' devices to be a huge pain in the ass. The only places it's not extremely shitty are the Switch (which still isn't great) and Apple devices.

Options between "we don't have tech in the house" and "wide-open tech, we have it all" are all some amount of painful, usually for no good reason.

(I remember once investigating how to do some pretty basic stuff for this in Linux, hoping to find something nicer than manually setting some executable permissions and firewall rules and then having to go back and change them all the time, and the closest thing to a guide I found was an old article from Red Hat that basically lead with "LOL, good luck you poor sap, Linux sucks at this" before going on to explain the various bad ways available to sort-of, but not entirely, accomplish it with a lot of work, and significant ongoing time-burden)