Monster Hunter World the game got so hard after some point.

As i heard from people the guardian and defender items are too strong for the beginning and makes you lose the hunting and item building feel you'd have if you didn't use them, so i didn't use them when i started to play. Everything was far too great. I have played rise before world for 30 hours i think so i know the mechanics and game was pretty easy to play. Like the saying that ' I am not stuck here with them, they're stuck here with me '' kind of thing. but after i got to the elders recess everything started to feel unfair. Bosses like nergigante, bazelgeuse and even if she's not hard as the first 2 i mentioned deviljho. Like don't get me wrong while fighting with them i don't even faint generally. but the fights make me use 8 of my mega potion's demon and armor drugs and so. I feel so retarded. Aren't this a big jump from the last bosses like odogaron which is a piece of cake. For only this reason i got a defender switch axe to a full level and got guardian armors and I am having hard time even with them. Am i a bad player or are these bosses are actually hard?