I have a similar 3D Printer and had a block so bad that decided to replace everything.

Throat w/PTFE throat
Heater Block
Nozzle
12/24volt Heater (as I have 12v and 24V 3D Printers)
Thermister

Then I had plenty of time to unblock --- I only did this once was so cheap to replace next time threw away anything that took too long to clean.