I thought the Wheel of Time series was great. The show makes some much-needed changes that are for the better. It invests in setting up a world most people won't be familiar with and without resorting to rape, murder, and incest to hook viewers. IMO Game of Thrones is more medieval Skinemax with fantasy trappings.
And if you think WoT was slow, then avoid the books. There are 14 of them IIRC, some of which people skipped entirely. I stopped after 6 or 7. People forget that Robert Jordan set the template for ridiculously long-winded fantasy books with little to no plot development that influenced George R.R. Martin. Back when writers were getting paid by the word and fantasy reached its peak in the 90s. Jordan died before the series was complete. Martin seems headed for the same.
For more standard hack and slash good/evil fantasy The Witcher on Netflix is pretty good.
As for Foundation I think I read it many years ago. Real sci-fi is an even tougher challenge to put on the screen IMO.