Hey there @JoeMusashi08! Welcome to the community! So ARTv1 is still available as ER showed, it’s just that old links to it are dead because in the last couple of years older marketplace assets were moved. However it is still only applicable up to 4.21 it seems.
Disclaimer: One or more of these links are unaffiliated with Epic Games. Epic Games is not liable for anything that may occur outside of this Unreal Engine domain. Please exercise your best judgment when following links outside of the forums.
Here’s a video showing off (a slightly older) importing rigs from Maya 2019, this might assist.
