Thomas

Please submit a second copy of that letter, but replace Windows with Android, PC with Mobile, Microsoft with Google, and Edge with Chrome.

My setup is smaller, but when my venerable old router died about a year ago, I acquired an Asus TUF-AX3000_V2 where I installed FreshTomato. One can login via SSH and dump all settings for backup. Likewise, individual or all settings can be done on the command line instead of the GUI. I have a script on my computer that reads CSV files with MAC addresses and more to apply changes in an automated way.

Yes, XMPP with proper TLS on the server side and Conversations or one of its forks (preferably fetched from F-Droid) using OMEMO encryption should be good enough. If you are brave or paranoid, give Tox a try: https://tox.chat/