1. Technology and screen time aren't the problems; it's the lack of passion and interests that is the root problem. Cultivate passion in your child and expose them to new things. You'll immediately notice a positive change in how they use their screen time to pursue these interests. When they watch gaming videos or unboxing on youtube they do that because that's their current passion.
2. Your control over your children diminishes over time. Build trust early on and allow them to make mistakes; these are invaluable teaching tools. It's better to teach them good habits concerning technology while you still have influence, rather than later when your control is limited.
3. There are real costs associated with not allowing your child largely unrestricted access to technology. These costs include social drawbacks, a significantly reduced ability for them to explore their passions independently, and long-term tension between the child and the parents due to a lack of trust.