TLDR below.
So, my modded Switch was banned years ago because I was new to the whole modding thing. I have a non modded non banned Switch as well. I send altered Pokemon to my non modded Switch, but it takes a long time. On 3DS Pokemon Bank I've recently started transferring Live Dex files (from here) to my saves, and transferring those Pokemon to HOME.
My question is, if I grab a Live Dex file of Scarlet/Violet and Sword/Shield, can I use PKHeX to put them in my Ultra Moon save file, and then transfer them to Bank, and then HOME, and have them deemed legit in the end? I know they would be deemed illegal in Ultra Moon. But would they become legit if they were moved to the game they came from (meaning, S/V or Sw/Sh)?
Can I use PKHeX to take S/V living dex pcdata, and place it in my save file of Ultra Moon, and transfer them to Bank and then HOME, and have them be legal in the end (even though PKHeX would note them as illegal since they're Pokemon that come after Ultra Moon was made)?