Hi all. This is an update to this post. I don't know what else the community can do to help, but I figured I'd throw some more content up there and give something bored people to look at.
Since the last update on that post, I tried working on the printer in freezing temperatures (not really but it's cold in this house) with extremely precise practices on assembling the hot end (the same hot end I had haphazardly assembled dozens of times and printed with zero issues) and yielded zero progress. Today, I tried a brand new PTFE lined heat break, along with a brand new Capricorn Bowden tube (I already had one but I needed more tubing for the heat break). Clogging in the same exact way in roughly the same amount of time as every other attempt. It's as if I've not tried anything, literally nothing is effecting the results.
I considered ordering a fancy micro-swiss or ed3 hot end, but at this point, including the stock hardware, I've gone through 6 heat breaks, 3 heat blocks, a half dozen nozzles and a foot of Bowden tubing, none of which did anything to fix my problem (or even make it worse). I would look to the extruder, but I outlined in the previous post the testing I did to rule that out (able to run >1m of filament at high and low speeds through the Bowden tube).
I'm at the end of my wits. Perfectly good printer cranking out multiple high detail prints a day, now completely useless over something so stupid as clogging. Where the hell else can I look? Could it possibly be some sort of software/firmware issue, where Klipper isn't sending or receiving the right commands or something? I know my slicer settings are at least good enough because I've tried both prints that have completed dozens of times as well as new prints with drastically reduced retraction. Do steppers need to be tuned over time? I don't think it makes sense that after a year it'd suddenly become so uncalibrated it's unusable, and when I tried calibrating it before I was just unknowingly calibrating against mild clogs, but I don't know where else to look.
I don't, but I've used numerous cleaning methods and am 99.9% sure that debris isn't causing the issue. (It still is happening with brand new hot end components right out of the packaging.)
Unfortunately this is the last good config. The printer had literally just finished a print and all I did was change the nozzle (done hundreds of times over the last year of printing) and since then it's never completed a print. I've also tried I think 3 or 4 different rolls of filament, one of them was the filament in the printer when it finished it's last print, so it was known-good literally minutes before disaster.
Also yes, standard v6 style hotend. I have a couple tests I'd like to run today to try to further diagnose my issue, if the issue somehow points towards the hotend I think I'm going to go for a micro swiss [or look into the hotend you mentioned if it's a drop in replacement (since I can't print any new mounting brackets...)]. I really don't want to get a fancy hotend since this printer is now available from the manufacturer for ~$30 more than the micro swiss. So I'm hoping it's something else.