Utilizing elytra? Sky, portal & giants

We explored dungeons, we explored oceans. Why not exploring some sky?

Firstly, I think some sky biomes could be implemented like floating islands or puffy (could require special enchanting on boots to walk) cloud terrains. This could come with a couple of mobs like birds or sky creatures. I'm not saying that flying ponies should be implemented but it would be cool to find a chest in some sky island.

Secondly, I think it would be fun to explore what sky has to offer after getting elytra. This brings my next idea: "heavens" portal. Not necessarily "heavens" but it would be fun to see another portal which could be, for example, only founded (ideally in some sky island) with the help of cartographer and could be entered, for instance, only if we place a dragon head on top of it (pretty much like we place ender eyes to enter end portal).

The portal could be the opposite of Nether - instead of lava pools and fires, we could see water and bright colours. Some variation is wanted after fighting all those gloomy mobs in the end and nether. And after having all this netherite armour and elytra, it would be fun to fight some giants. There are plenty of other suggestions on how the additional world could be built and what could it include. But I'm just saying that having things there "big" and "powerful" would be fun so we could utilize elytra and netherite tools. The goal of it? Not up to me :P

I know this is a really big idea but just wanted to share what sounds innovative to me.