RE: Immediately severely clogged after only 2 test prints
I haven't experienced any nozzle clog since I have started to use filament dust filter years ago.
I had only two clogs in my maker's life.
The first one was back in 17 and was caused by the foam of my dust filter (the exact same you posted!) that started to desegregate due to the filament rubbing over time. It was challenging to clean-up because the burnt foam is more sticky on the nozzle than on the filament. It took me about a dozen of cold pull to get it clean, I never ever used a dust filter since.
The second clog was during the 20s lockdown (😷) and was due to a crumb of cardboard, detected by the machine, solved by a single cold pull. Never experienced clog since, I often think that I am lucky when I look at the dust on some of my spools. 🤭
Filament breaking is another story. It looks like here peoples are facing to filament snapping, not a real clog. I noticed that the portion of the filament that has been dented by the extruder becomes more brittle when straightened. It is a general observation, not specific to the CORE One. It's like a pre-cut packaging, without this small notch you almost can't open it or you need to bite the plastic with your teeth.
I'll be curious to know if the new unload procedure from the recent firmware has worsen this issue?