Basically M+ seemed to have 5 IDs saved for Kimetsu, which led us to think it would be appearing until Issue #24 for sure and hence have 205 chapters. Thing is, that 5th ID has been filled by Haikyu!! which had its IDs messed, and so we can only confirm its appearance until Issue #23. As it has always been.
This practically eliminates the theory we had with M+ and only leaves the option of Volume 23 filling 9 chapters in order to not end next week. But it can always fill with 8. And not only with 8, because if it were to be the final one, we'd be talking about extras, afterword, and there's Popularity Poll Results XD.
And you know, the thing about the Pop Poll is kinda curious. Its results were planned for August and it could have been pretty much a situation of Volume 21 on June, 22 on July and 23 on August to finish the series. But instead, we just got an announcement today that Volume 21 will be released in July and the other two will be announced in the future. Lmao, what a mess.
At this point, I don't know anymore, so I'll just wait. It's impossible to figure out now.