Weird thought, but what if the "transcence" was about more then making Drizzt a "Planeswalker", but about setting up one of the next D&D 5e source books like Drizzt's Guide to Dragons, or Drizzt's Guide to the Planes, Drizzt's Guide to the Feywild, or Drizzt's Guide to Faerun?
I mean Drizzt previously really stuck to regions that RA Salvatore was comfortable with, such as the Swordcoast, Calimshan, Underdark, and the Bloodstone Lands, with drift stints in the Shadowfell and other planes.
This transcendence broaden Drizzt's horizons vastly, he was one with the whole multiverse at once, that means every part of the Forgotten Realms and even other D&D settings like Dragonlance and Eberron, so his knowledge could be vaster.
Drizzt is D&D's most popular character and they've been doing alot of different Drizzt collectibles (including life size Drizzt!), video games, etc..., so why not make him the "narrator" of one of the next D&D books, I think he's done it before in previous editions after all.
Drizzt Do'Urden's Guide to the Underdark
Drizzt Do'Urden's Guide to the Underdark in 2e D&D. Now that in 5e he's more more broader in his knowledge of the multiverse, he could do a guide to almost anything.