Invites terrible game design and invisible mobs/attacks/particles.

Well my main concern with poe2 is that just like poe1 the endgame bosses game design is just terrible.
Just like in poe1 to fight an endgame boss u need to spend a bunch of currency.
The sad part is, this is even worse in poe2, since the citadels spawn ratio is insanely small and buggy.
I've played for about 200h and found 0 CITADELS.
OK but i can just buy the fragments right?
Well every single invite costs aboud 200ex right now(and is getting worse) so this just creates the worst game design option about poe in my opinion.

1) U farm 200 exalts right, let's say u want to fight the endgame bosses to test the limits of ur build, now u can't use those exalts to make ur character stronger since the invite prices is 200exalts, this creates a very weird loop of, farming currency/gear to make ur character stronger but instead of using that for that mean, u use it to get an invite to fight a boss.

2) The sad part: This problem was "solved" in poe1, well, in poe1 in case u wanted to fight exarch and eater u needed to do a couple of maps, like 16, and u would get a guaranteed drop of an invite, that way u didn't really need to go to trade to buy invites in case u wanted to try the boss, is really sad to see a lot of the bad things of poe1 making theirs way in poe2 like rarity.

3) Now that ur character is strong enough and u have 200exalts to buy the invite to fight endgame boss, be ready because ur going to die to a invisible 1-shot mechanic, i really don't care about the game difficulty, especially at endgame, as long as it's fair, so the boss can have as many one-shot mechanics and be as hard as possible as long at is fair. The problem is, it's not! I have a PC that matches the minimum requiriments of software displayed at steam and still have a common problem of invisible enemies/particles and mechanics, THIS IS ALSO A PROBLEM IN POE1, it seems the game engine or whatever takes way too long to load stuff, and they "appear" in ur screeen before the games loads then, i had multiple instances where bosses would be 100% not loaded and fighting me, this is not as big of a problem in most of the game since u have enough time to survive the encouters until the enemie loads but in the case of endgame bosses it's impossible to beat them, i've tried arbiter of Ash about 7 times now and every single f***** time one of his one-shot abilities does not load correctly and i just get one-shoted from an invisible attack, also because of the 1-try sistem this just gets 100 times more frustating, if u want to have a boss being hard and only giving us 1 try at it, it needs to be fair. Sadly at the state that the game is right now is pretty bad, too many perfomance problems and too many problems fro poe1 that make their way into poe2, as much as those things make the experience very frustating, still a great game, i hope that GGG change their minds about this bad endgame bosses design and fix their engine. Peace.