I would be very grateful if somebody can point to an actually good blogpost/video that would summarize the current state of the domain. I mean, I remember some "quantum annealing" providers as far as some 10 years ago (I mean, as a service, as such D-Wave exists for 25 years now), but I never actually learned if they are truly useful for anything (like, real numbers, what amount of computation these thing can perform and if it's truly cheaper/faster than throwing a bunch of GPUs on it). From time to time there are some news feturing dope photos, about some new chip from IBM, that is useful for nothing, but a big breakthrough for reasons I don't understand.

But I don't really have a feel of what's going on, really. How many quantum computers there are, is there anything that is actually capable of performing anything more than just being an ongoing research prototype? Some educated guesses about how far can be some non-public projects by now? Like, is it possible that some secret CIA project is further ahead than what we know, or if it's even more unlikely and farther away than fusion power? Or maybe it's even more comparable to cold fusion?

I know, that this kinda exists as an idea, and apparently somebody's working on it, but that's pretty much it.