Since i joined the crypto world i didnt face any problem regrading wallets but i see that many people lose funds...somtimes the situation is normal like when somone share his private key or back up phrase in a scam website...but lets imagine that somone open a nwe wallet on trust and start using it without even keeping the phrase...is there a way to enter his wallet and make transactions without even having the back up phrase?
If they sideloaded the app through an unofficial source instead of Google Play then it is possible for this to happen. If you are going to install an APK then first you need to verify the checksum or PGP signature to see that it is a valid app and not a modified version that could have malware.