You ask about alternative and I will provide two, but for you rinformation both Taulman 618 and 230 can be easily bought in Europe therefore they must be still in production. Also, I'm not sure which kind of problem with PA12 you have, but if it's adhesion and warping, you can get good adhesion with PA12 if you print on garolite (fr4) boards. If they are thick enough they will avoid warping too, check here:
I don't know exactly which performances you expect for your part, but based on the specifications for Fiberlogy PA12 related to impact strength, tensile strength and softening temperature and HDT, I would say that you have two options.
If you are looking for a nylon-like filament for its strength and properties but you want it to print easily, like a PETG, you are looking exactly for Polymaker CoPA. It does not warp during print, it does not require a heated enclosure (in fact, they specify that the ambient temperature must be below 50 °C!).
See various reviews here.
Another option are Polycarbonate blends, where polycarbonate is mixed with other materials to make it easily printable, are a good choice. Polycarbonate is strong and routinely used for parts exposed outdoor.
Obviously you need a hotend reaching 300 °C for both alternatives.
I haven't tried Polymax PC personally, but the reviews and the experiences in various chats groups I follow are particularly good. It can be printed even on printers without enclosure, or at most placed inside a cardboard box to avoid air drafts.
Just remember however that polycarbonate is not resistant to some oils and some greases, that's why it's not used for parts in contact with bearings and so on. It becomes brittle, it cracks and breaks. It is likely not your case.
You can find two useful reviews about Polymaker Polymax PC here and here. Prusament PC is a similar blend with similar properties and printability.
Let me paste the second review if you doubt about its strength.
This is bar none the most printable for the strength polycarbonate.
Absolutely no warping printing at 100mm/s at 110C bed temp and 295C
print temp laying down PVA gluestick on glass.The printing experience
doesn't even feel like an exotic engineering filament because of how
easy it is to work with. Layer adhesion is very good. I print
primarily at 100% infill with parts that are routinely 10" wide by 4"
tall with no curl up issues. There is some shrinking upon cool down in
the x,y axis, but it is to be expected with a thermal plastic
(~0.6-1%). Now on to the strength. This stuff is strong. Printing a
1.5"x1.5" square tube insert, I misjudged the thermal shrinking (assumed too much) and the insert pressure fitted into the tube. Long
story short, after trying to back out the part I eventually resorted
to whacking on the insert with a hammer. For 30 minutes, I religiously
swung with a might that only Thor would understand on this black
Mythril-like object stuck at the end of my tube insert. Sweating
profusely I gave it one mighty cloud-parting swing to the side of this
object of torment. It broke the damn hammer handle in half. My heart
crushed, the sun fading, and my neighbors watching from their windows
I retreated a defeated man to my kitchen drenched in the sweats of my
failure. Too sickened to muster the courage to inspect my handiwork,
but too curious to look away, I set the object on my kitchen counter
and began the awful process of inspecting it. Like a strange autopsy
by cell phone light, I stared blankly at the effects of my entire
human worth condensed into hammer swings. Not a single dent. Not one.
"Impossible!"- I told myself. But the evidence of my lack of human
value lay before me for all to bear. Sitting there, mocking me, a
single scratch. Set there presumably by the object itself to torment
Two Youtube reviews follow.