Geeetech A20 multiple pieces printing issue

[Asici2]

Greetings,
i have a bad issue with my A20.
i manage to print small pieces without issues, but when it come to print bigger one or multiple pieces, the printer after a while stop extruding.
The filament seems to clog at the very last piece of the bowden, even if it is full inserted and touch the noozle.
What i did:
- i changed the extruder with a metal one,
- i changed the whole hot end, with an original new one
- i changed the bowden tube

printer settings: 215°c 50 speed, 5 mm retraction 80 retraction speed.
the printer is inside an enclouser i built, so it keep a constant 60° temperature.
I use CURA slicer.

i'm quite desperate, what could i do?
Thank you.