What tool do I need to remove this Joytech freehub? I have tried 10mm allen: too small, spins freely, with very little grip.

Hub brand: Joytech

On the outer side it has 9 ball bearings.

Video showing right/drive side:

                
            

Video showing left/non-drive side:

                
            





It is a low-end (BSO-ish maybe), 170USD hybrid bicycle, bought from Decathlon.
8 gears;
Bicycle model: B'Twin Riverside 120;
Derailleur model: B'Twin.

I'm not a bicycle expert, this is my first freehub removal attempt.
I'm not sure how this freehub is secured to the hub; any details are greatly appeciated.
I believe this one is a 12mm allen inserted through the non-drive side. 11mm is out there too.

Usually what I do is clamp an L-type one in a vise, long end up. A long socket would also work but it would need to be very long.