This Kulve stuff sounds a bit weird. I play solo almost exclusively so I'm not keen on having to find a party of 4 anyway, but what's this about the whole online session contributing? Will I be dependent on a whole 16 person session having their shit together?
You don't really need to have your shit together from what I've seen. I mean you do if you want to farm it super quickly and efficiently, but for general runs, it's easy enough that you just need people kinda doing stuff. Even if people wipe, they can requeue and keep going until there's enough overall progress. Also from what I understand, a single efficient group is enough to carry everyone easily.
Main tip if you want to be more efficient than the average pub, bring Partbreaker 3 in your build. Literally doesn't matter what you drop, because partbreaker is better than everything on this fight, it's a raw 10% "damage" per point, which is basically over double what anything else gives. Good ways to get PB3 is for example Uragaan chest+Partbreaker decoration in it for an easy +3, or a deco+partbreaker charm(need a teostra gem to make this) or if no deco you can try to fit both Uragaan chest+belt or belt+charm.
General fight tips are, break gold stuff, all of it, don't bother hitting the body it's just about breaking, if she sleeps, bomb her horns, use lightning if you have a decently fast weapon since she's extra weak to lightning in P1-3(for greatsword/hammer/horn etc, just use a normal raw build), ice for phase 4, bring a farcaster to switch gear between P3 and P4, or just to get more consumables, there's canons and stalagtites to shoot too, fire resist is good to have(if possible try to bring 20 natural fire resist so you're immune to burning).