What is a "DnD Elf"? Tall elves? That would be a Tolkien thing. Drow, maybe by name, but Dark Elves go back to Norse Mythology. None of the races, if used generically, dark elf instead of Drow, and don't use "the Underdark", are property of WotC. They're treading on thin ice trying to nail any of that stuff down, because other than specific named dragons/or specific races, the aforementioned Drow, for example, are things that they specifically created. Imagine, if you will, a world where The Elder Scrolls series had to have an OGL because they have Elves, Orcs and Dragons in the games. There's a reason they don't have to, because despite what some may think, Hasbro/WotC doesn't own them. It's relatively easy to stay away from WotC actual IPs and create systems that can compete with DnD. Some of the creators that I've been watching since this started only used the license because it was convenient. But they indicated that not only could they step away from it, but they already are.
Well, the "elf" name is certainly derived mainly from the "Alfar" of Norse tales ( mostly derived from the writings of the Icelandic Skald, Snorri Sturluson in the 1200s ), and there were certainly "light" "dark" and "black" elves mentionend. Similarly the name Drow is an Orkney/Shetland name, sometimes spelt Trow, which derives from Troll, as the existing Orkney/Shetland population was settled from Norway in the Viking era.
But none of these ( or other ) folklore renditions of an elf look like Tolkein elves at all, nor Gygax's dark elves, or DnD elves in general.
As I said, IP is squishy, but it is generally clear if something is a knock-off rather than orignal creation. Gygax and Arneson learnt this themselves when they published the original DnD with the "Hobbit" race, but immediately received a cease-and-desist from the Tolkein estate for IP theft. The replacement race was obviously the Halfling, which is definitely similar to, and inspired by, Hobbits, but had its own descriptions & lore which are different enough to not infringe on Tolkein's IP.
From what I have read about OGL1.1, it seems like the draft sent to creators for comment was probably drafted by WotC lawyers as a maximalist position for advancing the company's interests. It seems likely that WotC didn't properly explain what they were trying to achieve by the changes, so the draft was leaked as an assault on the community without context, and the community reacted in a predictable manner.
Whether or not you believe the subsequent "mea culpa" WotC published on DND Beyond doesn't particularly matter; but the reasons they gave for wanting to change the terms of OGL going forward are all valid. Unexpected uses and abuses of licence terms are inevitable as technology and society evolve, so licences do need to adapt; but this was a good example of how NOT to do it.
