Godot 3 does not support GLES 2, only 3, therefore until it does in 3.10 release, it (export targets for Android) will not work with certian Android devices:
Option is to try to compile master and run with the linked templates there, or to write the client in 2 as well as 3 (3 has had other stuttering issues before, so maybe a 2 rewrite is worthwhile).
Use OS.shell_open(url) to pop open https://godotengine.org/qa/29799/can-i-display-a-webpage-in-godot