iirc, the fallout 4 dlc provides a bunch of dependencies for modders and stuff to do more complicated things so big mods like this tend to require it. this has been a thing in Bethesda mod spaces for a really long time at this point.

I see it at $16 on sale at GOG at the moment, but that might depend on your region.

I got GOTY on humble store for like 8 bucks a few months ago, I’m sure similar sales will come again