It's done! If anyone is interested in trying my mod, here is the link:
https://www.nexusmods.com/titanquestanniversaryedition/mods/97

I've never used 3ds Max before, so I decided to pick the first option, and now it's much shorter while still looking quite natural, which I'm really grateful for. Here is a demonstration of my animation: https://imgur.com/a/CqGrTDr

And as always, I ran into new problems. This time, for some reason, the dual-wielding passive skills 'crossblade', 'doubleX' and 'AoE360' won't trigger their animations (gameplay wise, they work perfectly fine). For some reason, my Scorpos is still using his default dual-wield attacks instead of those special animations (except for 'DwAttAlpha'), even if I revert them back to the human ones. What could be the issue here? https://imgur.com/a/eGoVTFb. I even removed my added lethal strike for Sting, but nothing happened.

Or maybe I should just let it go? As I mentioned earlier, DW skills still trigger, but with normal attack animations.