M1 Screen sharing still broken?

On the serving Mac, select System Preferences > Sharing > Screen Sharing. Do this first.

On the M1 iMac, there is some configuration work to be done.

1. Drag and drop the /System/Library/CoreServices/Applications/Screen Sharing.app to your Dock
2. In System Preferences > Security & Privacy > Firewall panel.
   1. Click Firewall Options…
   2. Deselect Block all incoming connections (if this is enabled, screen sharing will not work)
      1. Click the [+] button and navigate in the Finder to the above Screen Sharing.app, select it, and click Add
      2. You should see a green incoming connection (this is VNC port 5900).
   3. Leave all other checkboxes selected
   4. Quit System Preferences
3. Click on the Screen Sharing application in the Dock
   1. Enter the host.local name and connect
4. When you are done, you can either shut down the remote Mac via its File menu, or just close the connection, and quit Screen Sharing.

What this looks like in practice on my 2020 M1 mini running macOS 11.4 receiving a screen sharing session from a 2014 Mac Book Air running macOS 11.4:

The firewall settings on my M1 mini (ignore the iTunes or FaceTime settings):

And what that MacBook Air screen looks like served onto my M1 mini 32 inch LG display via Screen Sharing:

Why would it be a bug ?

I never turn on my Firewall on my Mac computers - I have hardware firewall security at the router side turned on...