I found an interesting note in my study Bible that the Hebrew Bible puts the chapter divisions in a different place than our English translations. There, Ezekiel 21 starts where we have chapter 20, verse 45. I don’t see any more footnotes, so I will assume that chapter 22 starts in the same place in both languages. This is a good reminder that the chapter and verse numbers were not original to the the texts, but added later by scribes to help everyone communicate about the Bible. This is why the writer of Hebrews only says “it is written somewhere” when quoting the Old Testament. He didn’t have a chapter or verse to refer to at all. So, don’t take the numbering system too seriously; it’s not inspired by the Holy Spirit the same way the text is. (Though the Psalm titles might be. They were probably original to when they were written down, at least.)
All that to say, I agree that thematically these verses go together better. It seems like there should be a separation of some kind between God describing how He will restore Israel to the Promised Land and then talking about a devouring fire across the Negeb. The Negeb was a region south of Judah, the area where Abraham did most of his travels. The fire kindled there by the Lord would scorch all the people. However, Ezekiel is not believed, and the people ridicule him for making things up.
The Lord gives a further message, clarifying this prophecy. The Lord draws His sword from its sheath, the sword usually used against Israel’s enemies, but this time it is set against Jerusalem. All flesh, both righteous and wicked, will be cut off from the land “from south to north”. Babylon’s armies march from the north, but they will surround the city and send the exiles marching back to the north. Ezekiel is then to publicly mourn for Jerusalem, so that they will know how great and terrible the fate of city will be. The Lord has spoken, and what He says will come to pass.
Your words are righteous and true.