You can pick up a pulled laptop modem like the T99W175 from China for a low price, drop it into a USB enclosure (you’ll be limited to USB 2.0 speeds), and hook it up to OpenWrt. Or grab a GL.iNet GL-X3000 - the Quectel RM520N is already on board and runs over PCIe, so it’s quicker.

Then you can have basically unlimited IPs.

Android messes with your traffic far more than a bare modem (there's unavoidable NAT for one), and it has tighter thermal limits, so higher latency is expected.