Every app on your phone has access to your keyboard inputs.
Really? Even when they're at the background? That would be a terrible flaw in Android!
It's not a flaw, it's a feature.
I'm not an Android programmer but I read a lot about potential security stuff around digital devices. Any Android app can "subscribe" to be notified by system messages (don't pinpoint me on the correct jargon) if e.g. the clipboard changes and likely what is typed on the keyboard. Though I'm not sure if keyboard entries aren't some sort of private for the app that requested the keyboard entry. I wouldn't bet on it (a real Android dev surely knows better).
To boost security an app can and
should ask for a
private keyboard entry which should always be used for sensitive data. But the keyboard app has to follow this request properly, ie. don't do fancy online stuff and whatnot with that sensitive entry, particularly don't memorize or store the entry in some dictionary or blow it into the digital cloud. Decent keyboard apps should do this, but hell no you have no guarantee a keyboard app actually does it, unless you see and understand the source code or program it yourself.
The keyboard app in Android is a really sensitive and security important spot. There's a reason why e.g. Electrum on Android uses it's own keyboard entry method to enter recovery words. I praise Electrum for this. Unfortunately such security awareness is rare on other Android wallet apps.
I'm not entirely convinced that here the Android phone and the Swiftkey app are the main problem. The OP did some other bad things that he should avoid in the future.
- He handled recovery words on an online device outside of the original app (Bluewallet). Recovery words were fed into another wallet app. Don't do that on online/hot devices, period!
- He used 3rd party keyboard apps for entry of sensitive data. We agree, that's bad and should be meticulously avoided as you have no control whatsoever where your entry data diffuses to.
- He might have taken digital pictures of his recovery secrets. I don't know that, it was not talked about this. Of course, avoid this ever, too!
Recovery words are supposed to be backed up analog only, ie. paper or stamped in metal or similar analog and secure storage.
Maybe there's that went wrong, we don't know.
I can feel your pain. I would be totally pissed if that would happen to me even for the smallest amount that I would ever keep on a mobile phone wallet. I consider mobile phones as completely unsecure simply because a user does a hell of his internet shit on a mobile phone, install maybe questionable apps on it and just don't have much clue about security of such devices, not to mention the questionable update status of most Android devices once they get older.