It's a good intuition. Indeed you can see it as ReaderTaskEither (albeit on steroids).

The fp-ts author is also an effect maintainer and recommends effect for new projects. fp-ts is not dead, but it's core goals (providing Haskell/PureScript-like types and type classes) have been mostly achieved.

Effect is an ecosystem with different goals from fp-ts.

This is for all intents and purposes, fp-ts 3. The projects essentially merged, Giulio Canti is working on it and fp-ts 2 is renaming methods to ease the transition to it.