There is a 30-day trial that lets you export to unreal 10 times.
I think that the license does not give problems if you are not going to create content for others, and you only want characters for your game.
It is true that the store is very confusing and it seems that you have to buy a lot of things (it may be intentionally or the worst sellers in the world).
but if you just want rigid characters without headaches, just you need Character Creator 3 Pipeline only.
I don’t like the hair and neither the clothes. but you can also import clothes in obj and adjust them to the body and rigged.