Please also consider the GL-iNEt Puli (XE300):
- 5V 2A USB C connector and a 5000mAh battery
- SIM and [not tested by myself] eSIM support.
- Tailscale and Nebula available as a plug-in.
- Main network and guest network can be set.
- OpenWRT if you want the GL-iNET firmware.
I'm sure this is what commenter meant.
GadgetBridge even works without the need of accessing the internet, and open source app that gets regular updates and has a nightly build available.
I get my wearables and others from their list of supported devices https://gadgetbridge.org/gadgets/
Need the Maps data, the satellite picture, or StreetView? All these past years this WebView wrapper have been working like a charm https://f-droid.org/packages/us.spotco.maps