I'm trying to find the reason why my bigger printer suddenly decided to constantly create blockages as high as the PTFE tube in the cooling block (so a little bit above the heatbreak).

It's an older V6 head. The discolouring on the heating block comes from the single time the nozzle came lose and PETG was pressed through the threads upwards, that was a year ago though. I didn't change anything, from one day to another it just decided that (for both PLA and PETG) it'll now stop working properly.

Waiting on a stronger cooling fan (strongest Sunon I could find, the one with 9000rpm). Other than that I'm just confused why this suddenly happens.