Been a few days since using electron, but AFAIK electron can't be used as a wrapper for android apps, or can it? Or is their android app a web app wrapped into a "native" android app too?
Also, since this seems to be an issue since 2018, 6 years should be plenty to rewrite using a native secure storage...
Yes, in your head, and in your second factor, if possible, keeping derived secrets always encrypted at rest, decrypting at the latest possible moment and not storing (decrypted) secrets in-memory for longer than absolutely necessary at use.