I don’t understand why this has suddenly become so complex; you simply don’t give the kid a phone. That’s not a resource, that’s a lack of a resource.

If they’re super young, they’ll entertain without electronics. Give them a coloring book.

If they’re a little older, tell them to go use that Snap Circuits kit. Or here’s a ZX Spectrum and a manual on z80 asm. Or here’s a Nintendo DS and a Pokemon game.