System Settings --> General --> Sharing --> Enable Remote Login.
After enabled, port 22 will be opened automatically. If not, click on info against remote login toggle. Check Allow full disk access is enabled, try using administrator under allow access for option and set for All Users.
Also, a new user can be added by clicking "+" symbol at bottom.
Using terminal, test the SSH connection using another system with this command :-
"ping destinationIPAddress"
"ssh macusername@destinationIPaddress "- shows connection status of port 22.
If still unable to access, try to delete HostKeys and packages from the folder by following the steps:

1. Press Ctrl + R in windows.

2. "%LOCALAPPDATA%\Xamarin\Monotouch"

3. Delete the files inside the folder and try to connect again.