Update: Focus Mode is available in version 3.10.0.
Thanks for the feedback! Glad it's working well for you on Android. Regarding the rules – you can actually use 'Categories' to group them right now. It helps a lot with organizing and quickly filtering through your list when it grows. As for the Pomodoro timer, it’s an interesting idea, I'll definitely keep it in mind for future tweaks.
UPDATE: Blocking by categories has been implemented in pro mode.