Moving whole internal storage to external SD card

My phone is an (old, trashy, crap, …) LG l65 phone with custom ROM with patches on patches on patches on… This phone has 2 GB of internal storage, is fully rooted (along with custom recovery and ROM I said above) and current OS version is Android 5.1 (not 6 sadly). For now I only ran adb shell pm set-install-location 2 This command works very well, although in my case this isn't enough as installed apps make configurations right on /storage/emulated/0/.android and data folder. And are bigger than apps itself. I tried to run mv /storage/emulated/0/ /storage/sdcard1/internal/ && ln -s /storage/sdcard1/internal/ /storage/emulated/0/ but the command failed on the first subcommand (mv) exactly like here: [Can't move folder in Android terminal](https://stackoverflow.com/questions/34820052/cant-move-folder-in-android-terminal) and heard it won't link between devices anyway. Is it possible to move internal to external or do I need to suffer with non-updated apps, blocked SMS and new downloads?