-e: Using Input.inputString on Windows or MacOS builds works fine, even with non ASCII input (e.g. äöüß, scandic letters etc). The same on Linux only accepts ASCII. Unity's own GUI components allow non ASCII though.

-repro:
--Build the project for Windows/MacOS
--run it
--type ascii characters & non-ascii characters
--you should get all of them displayed
--Do the same with a Linux build
--NOTICE only ASCII characters showing up