What you are talking about is the operating system, not the cpu.
The ARM architecture allows much more performance for less power when compared to AMD64, because it runs simpler instructions.
The change to ARM chips on laptops will not make them work like phones, with the exception of much better standby.
Google SAYS they use the Signal protocol.
Without open-source applications, you have to trust these companies to do the right thing when they can track you and make money from it in every single step of the way. Same goes for Meta with Whatsapp.