About patk, basic attack and critical hit damage

i've always been some kind of math freak, figuring out what the best setup for different needs could be has always been one of the most fun parts of this game to me, but after god came out i stopped playing and thus lost contact with the game, at least until now.

i couldn't find any detailed information about how the game and its mechanics work now, so i thought i'd ask you guys for some help.

my memory is for sure quite rusty, but i think i remember something kinda-sorta like patk*77(*2withss)/pdef for basic attack damage, is this even remotely a thing now?

also, what about crit damage? again, if memory serves me right blunts used to have higher base crit dmg (2,5x? 3x?), while maybe all other weapons had just 2x? maybe i'm just making it up on the spot, i don't really know.
talking about crit dmg, how do buffs and epics add up? i think all bonuses refer to "base crit dmg", so for example let's say i deal 1k dmg with normal attack and 2k with critical hit, with both aq+baium rings it would sum up to 2.6k dmg? no buffs included ofc.

while not strictly on topic, how is raw patk calculated? i tried with 85 tyrr titan with different weapons, and with the lowest patk 2hw i could find (21 at talking island merchant) and no buffs i get to 2.194 patk, which should depend on passive masteries (both % and static patk bonuses), and this is fine, then i tried with heaven divider (342) and dynasty staff (325 and numbers went up to something like 3331-3391, but i dont understand exactly how that happened. finally, if i tried to buff up (just with rage and ogre) it went to something like 4091-4200, which seems a bit strange number to me, since neither 35%+15% nor 50% increases apply to a base number to get to 4091.

well, this was some kind of "stream of consciousness", if there's someone out there who likes math applied to l2-games like i do, feel free to share your knowledge and enlighten me