If the subject is interesting/useful I don’t believe forum software matters that much to us users. All those that you mentioned would work fine, I’d say.

Notification issues I have tried to solve with Bettertouchtool and Hammerspoon, but I havent been able to find notification API access in them. Though I don’t know if Apple provides such access to notifications. Use cases I have are reacting to Slack, iTerm, Mail and browser notifications as events. I’d like to access the notification content in plain text or object and then decide how to process it. Depending on message content, time of day, place, connected network &c I could put up rules on how to proceed. I could show notifications on touchbar or on screen in less distracting ways than what notification center allows. I could pool certain notifications and check them all in one place, such as bot messages from various slack channels.

Notifications seem easier way to get information moving between apps than trying to use their specific APIs (if such is even available). Sort of light weight RPC from apps to my custom tools.