Hmmmm, I would really post this on the K1 Reddit, but if you're not using creality print with the default profile for the K1 I would try that first...
If you got through a whole spool without any issues I really don't see your extruder going bad in that timeframe, but idk
When it's still going but not actually printing anything do you hear any clicking, can you see if the extruder gears are still turning and trying to grab filament and push it through? (On my K1 Max I can see the extruder gears from the back side of the print head), maybe either extruder gears giving out and not being able to grab the filament, or your nozzle listing the heat it needs to extruder properly