Here is an example of installing a drain by trenching it in. This is a koi pond where either a liner goes above it (drain is two part and clams onto liner) and or concrete is poured over the drain pipe etc.
Most koi ponds are basically low density RAS's.
There are several types of drains sold for koi ponds that could be used in an Intex pool.
You can also build your own. Note the molded in air line attachment. This keeps keeps the airline out of sight for aesthetic reasons in a koi pond.
Btw the way the dome serves a purpose. Without it there can be a vortex above the drain which can impede the self cleaning. They are appropriately called anti-vortex domes.
