Personally, I eventually made loadouts for every element with a generic one that had Stun debuffing. It was a bit grindy to do that. I had short swords and guns/bullets for each element. This method worked all the way till the final boss. For the sequel, so far I've gone the polar opposite route and have a non-elemental short sword and gun, then just swap out the bullets as needed.
Bullets at Difficulty 8 with the Sequel are still black magic to me, and I've just gone with generic elemental Bomb bullets. Functionally it seems to work for me, modifying them seems to produce negligible results. That being said, the Wiki sample bullets are crazy good, but I can't fathom how they came up with those. Anyways, the generic Bomb Bullets from Assault Guns seem to be pretty good for breaking Chi You bonds and the Side Armor of Tanks without much precise aiming.
If the RNG Abandoned God Arc Gods aren't smiling on you, there is always the Upgrade Slots and I think there are Trigger Happy and Frugal units that you can craft for similar results, though you may have to go up a couple more difficulty levels to unlock 'em.