Yeah, that too, and it really is one size fits all.
Red, I checked and while Heist definitely has ambitions towards sustainability and a couple of products with recycled nylon (tends to be open knit like fishnets), I'd say they're not at the forefront of it.
Wolford has some cradle to cradle certified ones which I'm curious about as this isn't really a certification I see much outside of my work field so I know a lot about it (got a whole indoctrination and met the people that set it up when I was a student) so I know it's not a bit of greenwashing and requires a lot of long term commitment from the companies involved. Aside from the Swedish Stockings (which I like) I've only found recycled ones at Arket, but I think those are part recycled part new, SS too, I think.
I also find Wolford sizing just right for me, Poppy, Fogal is also good when you follow the chart (you need to be very petite to fit a size S) but I suspect no good for tall people.