We can't trust apps from playstore anymore
That's nothing new.
You should have never blindly trusted them at all.
100s of apps from play store are infected with malwares and keyloggers,do not download apps from play store anymore,if you need any app badly find their website and download from original source,
Unfortunately quite a lot of apps are not open source.
And downloading it from a website is even more risky than using the playstore.
The playstore is somewhat moderated. Malware is going to be removed once recognized.
On a website, everyone is free to host whatever he wants to.
What most of these apps do is uploading users data to their own servers which can result in stealing your wallet keys too
No. That's simply wrong.
An application on your mobile can only access its own app data.
If you grant file system permission, it additionally can access the external memory (i.e. SD card).
Application encapsulation is a security mechanisms of android which ensures that each application can only run commands and access files in its own user context.
Well.. except if you root your mobile, which you should never do at all if you store sensitive information on your mobile.
Please don't spread misinformation.