SUCCESS! :0330: With a respectable 325 hours put into the game, I have managed to unlock the paraglider and can teach you all how it's done:
First you need to do all quests you can find. Major quests, temples, shrine quests, shield surfing, everything.
Then go beneath Hyrule castle and defeat the Demon King.
After that, make sure your save has a star (see second image). If it does, head back up to the surface and go talk to Purah in Lookout Landing. She will have new dialogue and will give Link the paraglider after some errands within Lookout Landing like getting to know the people in the base.
I'm aware few people might feel up to the task; but if I did it, you can too! :0460: Now got get that glider! :0330:
https://detroitriotcity.com/media/ad23600fa951383888b8335086fb4381e8cb44c77604a8cad2695f2825dcee9e.jpg
https://detroitriotcity.com/media/71d7332347640458c2397cdc8d47cb5708a2b7595990aa6bf95d9d7215a95ad7.jpg
https://detroitriotcity.com/media/69fddc024114d87a8727de64db01c598a30db6548108afbda988b17566299b3d.jpg