I look for the source-code of the corresponding applications:
simplex-chat -> https://github.com/simplex-chat/simplex-chat (Kotlin and TypeScript)
tutanota -> https://github.com/tutao/tutanota (TypeScript, JavaScript)
So summarizing: Exactly problematic languages being in execution. To differ here: Build-time for compilation is one thing, run-time for running those (in the AppImage) is questionable. See especially NodeJS is a problem here as it needs dependencies to build and download them in special versions again at build-time and uses them therefore also at run-time.
Human being in favor with clear principles and so also for freedom in soft- and hardware!
Certainly anyone who has the power to make you believe absurdities has the power to make you commit injustices: For a life of every being full with peace and kindness, including diversity and freedom. Capitalism is destroying our minds, the planet itself and the universe in the end!