I mean if it's just the def down you can use 3points in def down immunity or the charm, but I'm not sure it's that. Maybe I'll try it out next time I fight Jho but unlike vanilla where I had to fight him several times to get a bunch of the weapons, in IB his weapons are just pretty much all shit since negative affinity is a much bigger issue now with max might being shit.
Atm I'm mostly still trying to get a gold rathian investigation, I've only gotten her+another monster, meanwhile I have like 9 silver rathalos investigations, keep getting these instead. I've also hit forest 7 after farming coral 7 a bunch and dropping it, and once I got enough scarred garuga items and another Kushala kill I'll drop it and maybe get Rotten Vale back to 7 for temp Brute Tigrex and Vaal and then just go back to Coral for Namielle(I have like 70materials and 5weapons augmented already but eh). It surprisingly isn't that long to level these guiding lands shit, people made it sound like it was horrible but all I do is just kill monsters, no fancy trap spamming shit or whatever but just killed like 3.5monsters and get a level so it goes pretty quickly especially when luring low tier shit, they give the same progress but you can kill Jagras/Girros/Kulu/Tzitzi in like 3-5mins just mashing buttons.