[rendx]

There are gateways to onion services and IPFS, so those are "indexed by search engines" without any change necessary. Furthermore, any search engine has to be adapted to the medium used, and there are specialized search engines for pretty much anything including Freenet and I2P etc, so saying that the "dark web" is a subset of the "deep web" is incorrect. There is some overlap, but it's not a "part of" relationship.

The problem is that there is one (academic) definition of "deep web", but many incompatible definitions of "dark web", invented by the media basically for whatever they want it to be.