What could I add to give it more character?

Hello! This is my very first time doing a project like this and i think it is okey-ish. It’s supposed to be a nether hub but i had no idea what to do in the build so i just made some mini biomes :))
i really dont know what i could add to the build (especially the portal, it looks plain.) and i would appreciate any suggestions!
The photos are not the best, sorry for that😅