I've been looking for at least a year now for a solution but I can't find one as I've never seen an issue like this one before.

There's multiple accounts in this house and you would think PSO2 is just PSO2 and would work the same even if all is played on one or multiple computers... but no.
Out of the 3 accounts, the Xbox controller works exactly as it's supposed to. The 3rd one? Unless it specifically uses something like Xpadder, and even that it's very buggy and faulty, the Right Trigger will not work and we can't find the solution at all.

It's not that the game not picking up the Right Trigger, or it would act the same on all accounts, but on just one, it's like the Right Trigger is not there/broken.
Going in Calibration when it asks to touch LT and RT... it recognizes the buttons, but dodging, multi selecting, blocking, etc won't work at all.

Going into the button configuration as well will not work as if I head to the Evade button and by chance accidentally turn off RT to something else as let's say LT... I can't revert it back to RT as even there the button isn't working.
Why is this happening and how do I fix it?

As I said, it's just one account that does this and the Xpadder attempt is a really bad band-aid for this problem.