I'm writing this carefully as to not jinx it, but i'm half sure it's fixed now. I had to remove the bezel first to make sure nothing could be damaged on the die side, then torque my snap ring pliers hard first counter-clockwise, followed by clockwise to break the red loctite on the threads. It was in hard enough to permanently bend the pliers, but the loctite wasn't the sole villain in this; there's more glue-like gunk and the aforementioned unknown debris under the retaining ring and seemingly seeping out from inside the driver housing.
The ring got a thorough rinse and deep cleaning first with a needle and toothpicks, followed by a few turns on my leather strap to polish it and then rinsed again with isopropyl alcohol, the board got a similar treatment with the goop being first poked off with a toothpick, then rubbed off with a q-tip and alcohol, lastly lightly polished and rinsed off. I tried to get as much of the sticky stuff out of the driver housing as possible, then slapped it all together while it was still all nice and clean.
As i began my post with i hope i don't jinx this now, but the light managed to stay on from a good while before i went to bed to when i woke up and turned it off, 5 and a half hours. I can't promise this'll last or if it's just a lucky fluke right now, but so far i'm happy with it.
My last thoughts for now in regards to this are that i'd very much like to know what could have caused aforementioned glue-like gunk and the debris, i've tried to find old pics of the inside of the drivers but many have been lost to time and hosting issues. If anyone has any info i'd be grateful.