Hello Richard,
Changes happen quickly. If you go to Dev channel, you will be at the point of no return as this channel is not tied into any specific release. This may change again next year. Build 22449 is going to become version 22xx next year. If you go to Dev, only way back is clean install.
Beta is currently 22000.176 version 21H2 so remain in that channel for now. As soon as MS decides to move it to RP channel or Release, the channel options will change accordingly. This will give you the option of leaving Insider on a Release version of W11 when that time comes. It currently is not available in RP, only W10 is in that channel as it stands now. Soon both W10 and W11 will share RP channel.
Yes, it does get confusing. There should be couple weeks once that change happens. Advise keeping up to date with the blogs weekly. It will happen very soon as MS has finalized release for Oct 5th for 21H2.
Edit: What is displayed on your Windows Insider Page in Settings. Are you in the Yellow Zone by any chance? Can you move to Beta channel? Kindly post that picture as well. Appears you are compliant being offered 22449. Have you run the following elevated commands, as I think you mentioned Beta was not available. You had mentioned you could not change via registry.
At the elevated command prompt, type and reboot after done, worth a try:
bcdedit /set flightsigning on
bcdedit /set {bootmgr} flightsigning on