A10M - printing quality goes down after few prints

[Sifon]

Hi,
I have A10M with BL Touch. The the printer has been set up correctly. Print output was great. But now, with the same settings, same filament the printing quality is very poor. The printer started printing like this after approx. two spools of filament (1kg). Printing only PLA/PLA+ and using only E0 extruder. No mixing. Using only .4 nozzle
What I tried:
1, new bed leveling
2, tried filament from other vendors
3, changed nozzle (3 times)
4, changed extruder (E1 -> E0)
5, lower printer speed and rise flow

I don't know what to do next. The photos are from last print (25 mm/s speed, 105% flow, 205°C, bed 65°C)
Does anyone have any advice?
Thanks
Sifon

[mobiobi]

That looks like under-extrusion. I might confirm there's no obstructions in the hotend. I once had some a piece of hardened filament half clogging a nozzle that looked like that, so maybe further up in the head?

I just bought am A10M off eBay, still tweaking it in.