Nobody here can assist with this.
Developer access isn’t the master key that you’re imagining it to be, and doesn’t provide a path to bypass security and access devices and networks. That whether via AirPlay, or otherwise.
Enrolling in the developer program does provide the ability to do on-device app testing, but your enrollment is not relevant to and not a path to resolving your reported device and network security issues.
Developer enrollment enables limited access for testing-enabled devices.
Developer enrollment doesn’t grant access on devices not enabled for testing, or access to remote exploits whether possibly via AirPlay or otherwise.
The Apple Developer program Account Holder status is intended as part of an organization that is managing a group of developers working together on apps, and—beyond enrollment being a prerequisite—is unrelated to program enrollment and unrelated to device or network access. It is part of coordinating a team of developers.
Are iPhone exploits possible? Yes. Based on available information, iPhone exploits are also quite rare, very targeted, and are very expensive. A remote exploit with persistence can be worth most of two million dollars, and the related tooling is worth much more.
Are you a target? We don’t know. If you are a target of a well-funded adversary, you’re also past the scale and scope of what assistance can be provided here, too.
Making these discussions all the more difficult, it is ~impossible to prove a negative. Nobody here can prove you’re not hacked.
And nobody here can help with a case such as “They taken control of my families devices and network”, as that’s a whole lot of detailed work and direct access to it all, past the usual and generic recommendations to reset all passwords, reset all devices, reload all, and to particularly replace any older or outdated gear, etc.