Earlier quoted context omitted.
You're doing the right thing. w.r.t. "what will you do when they get older and jealous?" , learning to deal with jealousy is a good lesson to teach kids. Giving a kid everything they envy and demand is how you raise an entitled brat.
They aren’t jealous of the tech. They are jealous of not being included. They might not get invited to events or understand their friends jokes because they weren’t part of the group chats. This can make them resent their parents and give them social anxiety. Kids can be very cruel and lack the empathy skills to understand why their friend isn’t allowed a phone. Overdoing it either direction can be a serious mistake.
It's better to instill in kids early that it's important to cultivate deep rather than wide social connections. Teaching your kid to stand up for themselves and make friends that don't care about blue chat bubbles or fashionable clothes is necessary. Because there's always gonna be some group you're not going to be cool enough to be a part of. Maybe you're not pretty enough, athletic enough, maybe your parents aren't rich enough to send you on the holiday trip the other kids can go on, sooner or later everyone's going to learn the lesson that this isn't how you build genuine connections.
I noticed this even as an adult in my 20s, people who hadn't ever learned to deal with social rejection carry that teenage group behavior into their own adult life and can't deal with exclusion.