Do you have the correct thermister type set in the firmware? If there’s a reporting difference that could be why. (This one bit me on my first 3D printer rebuild, now I’m way more vigilant about it)
Without a nozzle installed are you able to push the filament through the hot end? (This one bit me on one of my printers due to faulty hot end and there being a piece of metal partially obstructing the filament path. Sucked to diagnose but was an easy fix once it was found)
Is everything on the hot end tightened down still? (This one bit me a few weeks ago after a couple bolts on my hot end worked themselves lose after months of use)
Is your extruder still functional gripping the filament? If it can’t grip properly (or is jamming) this can cause clogging issues.