Thanks all for your input !

So yes /sdcard was /storage/emulated/0 and it’s a real sd-card.

That was indeed formatted as FAT, I reformatted into EXT4 (from a desktop Linux) put the SD-card back into the phone and started the phone.

Ive tried (in the phone)

su
chmod 777 /storage/emulated/0 #yes it's still mounted as emulated !
stat /storage/emulated/0
#...
#Access: (0771)
#....

So I’m still blocked… any ideas ?

Thanks.

I’ve found the most simple way (for my case) adb shell 'a command'

example

adb shell ls /

Thank you all for your input… but it seem my question is still not fully answered…

let me rephrase, I’m not looking to have a GUI to transfer files, but I would like to execute terminal command remotely (from my computer) to my android phone. Like SSH .

So I’ve read that I can install a SSH server on my android phone… (If you know some’s (FLOSS), I’m all ears) Or if you know a better way than SSH I’m all ears too.

Thanks.