Apple Cinema 20 Display on MacBook Air M1 2020: stop the flickering?

I am trying to have my Apple Cinema 20 Display work as a second screen on my brand new MacBook Air M1 2020. Read this article and other videos and bought the following : - Apple Mini-Diplay Port to Dual-link DVI Adapter - a basic usb-c to Mini-Diplay Port adapter It works -almost- all right. The Cinema Display displays. But I get like parasites, like small zebras (like a bad rection on an old TV set) and the screen gets black for half a second to 2 seconds every now and then (from 3 seconds to a few minutes, no pattern). When image comes back, sometime there a sort of an horizontal line of raw pixels scrolling from top to down of the screen between older frame displayed and the refreshed one. Does someone know what could be causing this? And how to address it. It feels like I am almost there... but not. Thanks a lot to this community in advance.