Wouldn’t it be more effective for the government to develop a highly secure communication app, known only to individuals in top-level positions?
This app would be discreetly installed upon appointment to a senior government role and automatically removed upon departure from office.
That's ... that's the communication network they're avoiding? Because the problem is not _which_ app, it's that it's _an_ app, on standard hardware, on the public internet?
No, not for classified comms. They already have secure comms and SCIFs but they're not using them. This is what they should be using. And they should be following sterile opsec so they don't carry tracking and listening devices into classified meetings or strategy discussions with decision makers.
They do need better opsec for unclassified and personal comms. It would be nice™ for them to have a Signal-like app controlled by the NSA because depending on Signal or WhatsApp is vulnerable to a malicious insider. Few Meta employees have security clearances, while I don't know about Signal.