Probably a moot point by now but Korg Pa’s have a very limited expansion capability as far as Sounds are concerned.
Unlike Styles which can run off a thumb drive Sounds need to be loaded into the limited internal memory.
The moot point is that getting hold of any Pa is very problematic at this time, especially the Pa4X which if the rampant rumours are correct is being replaced by a ground up new model.
It has been quite a while since the 4X had its OS updated that unlocked extra features but the 1000 & 700 have had only minor bug fixes since their release in 2017.
I see Global Sounds have contributed to this thread, over on the Korg Forum praise is heaped on their products, do check them out yourself.