Dubstep is just as much a recycled genre/subgenre as anything else?
If you’re after something new to your ears it really shouldn’t fit neatly into any genre, right?

I have to disagree.
There is obviously a use of dub basslines but how it was used and everything else about it gave me that buzz I only get from a new genre.
That moment when you’re witnessing the next step in the evolution of electronic music.
Same as I had when hearing jungle for the first time, even if that also had faster recycled loops.
It was undeniably new and a genre in itself.
TBC it’s not the being ‘new’ that is important, but the fact that I have a lot of stuff to listen to from artists exploring the new genre.
I really like floating points BTW, the rest I haven’t heard of.

who was doing lush layered multi instrument compositions like this over electronic music pre-2000 not named Bjork?

I think there’s a few.

You name some individual artists here, of course there are plenty with their own unique sound, for me Autechre is the best example.
So yes there’s plenty of stuff to listen to, old stuff, cumbia, folk or whatever, but as I said, it’s been a long time since I’ve heard anything that can be justifiably labeled as a new genre in electronic music leading to a wave of artists exploring that specific discovered road.