Q: How to avoid loosing my settings?

A: To avoid loosing your settings follow these steps:

Android OS

Generic apk: Backup /NeutronMP folder with all its contents to a safe location. /NeutronMP is not affected by uninstallation.
Android 11+ apk installed via Google Play Store: create source entry to internal /files folder which is a file system sandbox of the app and which also contains NeutronMP folder with settings, activate internal FTP server in Neutron's settings and point it to the newly created source entry /files, access FTP with any FTP client (FileZilla for example).

Apple iOS

Backup /NeutronMP folder which is located inside the /Documents folder. To access /Documents folder use iTunes for PC -> select iOS device -> Apps -> File Sharing -> Neutron -> drag and drop to PC the /NeutronMP folder.