Your best shot is creating an issue for Mendix and I hope they get this solved soon because more people will suffer from this.
This seems not an easy fix that work for all languages and combination of device and app language. There are some pain cases with copy past and thousand separators too.
This pain is solved by bank apps in a common way with 2 input, one for the whole number, one for the fraction.
yes, this is not just a mendix issue, but a global issue.
copy pasting any numbers into any spreadsheet will give you a headache.
so you have to copy paste it into texteditor, find and replace all (atleast that is how i'm doing it).
maybe you could do the conversion in mendix somehow?
@All any worakble native solutions found for the comma drama? which is still not solved by Mendix R&D/Samsung
Found a Woraround without having to install gboard:
if you do not use English (or any other point based decimal formatting language) allocate that as language for Android users based on devicetype/systemname. via this route users without gboard installed can still use comma (point) seperate values. the grammarly correctness was less important than getting a Google keyboard installe by Android users