I think “no-self” and “emptiness” are really bad descriptions.
If you press people on this, they often wriggle with “well it’s no fixed essence of self” or “it’s actually emptiness of inherent blah blah”, but the phrases are still very often used un-wriggled… and the wriggling is unconvincing anyway.
IMO “fullness”, “everythingness” point at the experience better, and emptiness was almost exactly the wrong description.
That said: my experience was the one labelled “Big Mind” in this diagram from Roger Thisdell’s (related article), so it’s possible that “no-self” and “emptiness” are simply describing experiences I haven’t had.