It might be an issue with concentricity. If the nozzle is not perfectly centered it creates a step that the filament can snag on. It can then cause the already softened filament to bunch up during deretraction forming a plug in the heat break. I had this issue with cheap nozzles. Everything starts fine and after a few layers it all stops for apparently no reason. Cranking up the heat makes it better for a bit, before making it worse

That looks like a failing thermistor or heater cartridge. You might want to swap out both the thermistor and the heater cartridge at the same time. Had something similar happen to me and it turned out the failure of the one, likely influenced the other to wear out prematurely. The cartridge wasn’t exactly broken, but seemed to have a less consistent response curve. You can test them separately, but they are cheap enough that it is not worth the hassle