The end goal: An Android phone running as a VPN server in my parents home. The phone has a sim card with data in case WiFi is off. I can connect my Windows and Android device to this VPN server and act as though I am part of the home network.
What I understand: I’ve rooted phones before but haven’t flashed Debian or any other Linux OS onto it. I am comfortable using Linux (used Ubuntu and RHEL for years). Setting up a VPN server on Linux on android shouldn’t be hard.
Challenge: I have 3 spare android phones at home (Samsung S10, A50 and a Xiaomi). I’d like to run a VPN server on them without changing OS.
Option 1: Run Android OS as is and run VPN Server on it. This let’s the device connect to the Internet through SIM data in case WiFi not around. But I’m unable to find tools for that. I’d like advice here.
Option 2: Root device, flash Linux onto it and run VPN server. Catch is I cannot use device’s sim card (or don’t know how to). Advice here would be appreciated
Option 3: Buy a new raspberry pi. I’d like to exhaust my other options before going to this as a last resort.
Thank you for reading this long post and I’d sincerely appreciate any direction, guidelines or pointers on where I can discover what’s right for me.