I have a UniFi system at home, and then use a custom WireGuard config it generates on my iPhone to connect. It leverages the iOS VPN switch, just like turning WiFi or Bluetooth on and off. Works amazingly well. Should support Android, too, but I don’t have an Android anymore so no firsthand experience there.
They also have a proprietary thing called Teleport, but I don’t use that because it relies on using another app they publish instead of just the main OS user functionality.