Here is their reasoning, basically summarized as "it's easier to get everything for games into a new language than bolting it onto an existing language". I also recall seeing a blog post where they said their initial implementation of GDScrip took fewer lines of code than embedding Lua did.
Note Godot does officially support C# and C++, and there is unofficial support for other languages too. But they commonly recommend GDScript for beginners.

Fairphone is well supported by open-source Android distributions like Lineage and /e/OS. Not all Android is involved with Google.