Minecraft RTX Cliffs&Caves

It hasn't been a problem up until now, but having big Portals open to the sky has a tendency to trap Phantoms in the Nether, so I'm putting a big box over the Gold farm Portals.
Seeder map (base is at x-380,z380) :
www.mcseeder.com/?seed=115103...
Twitch livestreams: / sckchui