I am inclined to think that what will be of most use to you will be the references to using a stretching device using the "friendly plastic" or "polymorph" as described in
this thread.
If this is causing problems with peeing, you have clearly developed a severe
secondary phimosis - that is, you
were previously able to retract, but now can not. This
must indicate some disease process, which means you must
treat that disease process in order to make it possible to stretch.
It is a reasonable presumption (given the long duration) that chronic low-grade infestation with Candida is the problem and that you will need to treat this - probably
continuously - in order to achieve the result you want. The "Cortimyk" (locates you in the Scandinavian region) sounds a good start for this, though a (more) potent steroid, still combined with an anti-fungal, might speed the stretching.
I am curious about a few aspects - is the difficulty you have peeing simply a matter of directing the stream, or is this substantially delaying bladder emptying - which would be accompanied by extreme "ballooning" of what you describe as an otherwise perfectly elastic foreskin?
It is interesting that you mention no episodes of overt inflammation of the remainder of the foreskin. Have you had such? This otherwise demonstrates very clearly a most significant point - that all the problems people have with the foreskin are caused by
external factors, the foreskin is actually very effective at maintaining its health and having urine underneath is
not a source of problems. It is only the opening of your foreskin that is so affected - because that is the only part that is exposed to the "outside world"!
Now you have not mentioned sexual activity other than that erections are not a problem. A foreskin with such a tight phimosis, unless there really
is a major disease (notably Lichen Sclerosis) present, will necessarily have been fully stretched to
easily accommodate erections (which are virtually unavoidable, frequent at night) with perfect comfort, and with it always protecting the glans, masturbation is very easy and comfortable, as will be intercourse, though the latter may suffer from some reduction of sensation. What has been your experience here?
So in summary, I suggest you start by using the Cortimyk on a regular basis - twice daily. Given that it is a
mild steroid, you
may use it as a lubricant for stretching though the available information suggests
some risk of irritation due to the preservatives it contains. I think you
would benefit from a stretching device as described
there, which could initially be crafted with sufficiently small tips or "shoes" to fit the small opening you describe (and it may in fact, make it easier to pee with the device in place).
Note that the tips of the shoes should be made quite bulbous to minimise pressure and should always be as wide as possible. I suggest a modification of the design illustrated so that the "shoes" are actually folded
inside the "U" shape of the "spring" so that when in place, it actually lies comfortably back against the foreskin and shaft of your penis.