I doubt it. I admin a lemmy instance and a regular fediverse instance, and I use them both very differently, because their interfaces lend themselves to different uses. Even though they can communicate with each other, trying to navigate a large number of lemmy groups from Hajkey would be annoying, and trying to follow specific users from lemmy would be annoying.
An all in one app would mash that all together, which would probably be overwhelming and confusing