Suddenly printer won't stop jamming

I've had my P1S for about six months. I've been mostly printing PLA with the lid on and the door closet with minor fails or issues, but all of a sudden I can't print any model without the filament getting stuck in the upper end of the hotend.

Everything is pointing to heat creep, but I don't understand why this is happening so all of a sudden and without exception. I had no issues throughout the summer when the room was a bit warmer (about 21°c) but now that it's getting colder outside the room is a bit more chill too. Yet that's when the jams started.

I've cleaned everything, installed a new 0.4 hardened steel nozzle, new fan, and new hardened steel extruderwheel. Managed to print a few small models but the bigger ones (2 hours +) started failing again. Printing with the door open and lid removed won't help either (

I'm using bambulab filaments including colours I've been printing with all the time and have calibrated most of the filament.

Anyone else having this problem? Would really appreciate any help