Your description would make the most sense and is what I would say as well.
I’m sorry but I don’t know. If the date has been released, I didn’t see it. It shouldn’t take that much longer for it to be release in Japanese (I think. Don’t quote me on that) and it could be a while for it to be released in English. At the moment, volume 22 is still scheduled to come out in November, so volume 23 would be released in English sometime next year. I hope that answers your question ^^
Yes, unfortunately. The 23rd book is going to be the last one.