Before I wanted them to have a phone, I got a second d phone. It was my phone, not my kids phone. I would let my child take it when they went for a ride, or stayed over with a friend, or whatever. But it was my phone. If I had to take it off them, I wasn’t taking their phone, I was taking my phone. The difference is important. It also gave them a chance to learn appropriate use, and normalised me being in control of it. By age 10-11 the phone was basically theirs, in their hands, but the control is still mine. So my advice is don’t give the phone to your child, especially it as a present. It’s more difficult to take something of theirs away, but if they borrow something of yours, it’s much easier.
The sunk cost fallacy of wizardry. Come on man, just one more incantation, just one more and you’ll be immortal! It’s always just one more incantation!