It's been too long, with too many Skyrim re-releases... Apparently I already own "Skyrim Special Edition" but there's a "Skyrim Anniversary Edition Update" DLC that came out in 2021.
Sticker price is $20 which is absurd since I bought the entire TES Anthology boxed set for that much on Amazon lol - but it turns out Steam keys for it are always on sale somewhere. Picked it up on Fanatical for exactly $9 USD after tax and 5% off coupon code.