There's no shame in using the elevator. You'll miss a lot of loot and baetyls, but if you only want to clear the dungeon, that will let you skip most of it.

There is nothing wrong with farming merchants and exp to get better gear / rep for Bethesda Susa, it is known as the great build check for a reason.

Personally I would recommend getting the weathered skill and 50+ cold resistance as well or a ton of blaze injectors before going in if you plan to clear each floor otherwise a spiral borer will mostly let you skip everything.

Rimedryks are the most deadly common threat, you need to either make unshelled reptiles neutral or have enough cold resist + overwhelming firepower to take them out very quickly.

Normality gas grenades and / or high quickness make killing twinning lampreys easier.

If you don't want to over prepare then don't enter without a force bracelet, force bracelet + blaze injector + recoiler should get you out of almost any situation in there.