Today, I made some more progress on SubNot, allowing management of Telegram subscriptions, as well as creating filters. The video below shows the full flow on Telegram.
The filters on the button allow to send notifications to only a subset of subscriptions. I will post more tomorrow, with the management of Browser Notifications, as well. I think it is almost ready to be able to integrate on websites. Then I just need to make the whole website for configurations, etc.
Other subscription options will come later.