PINE64

The title of the post says it all I guess. I'm interested in a Pomodoro style timer which vibrates (to avoid annoying people) every X minutes.

I have a sealed version with InfiniTime 1.2.0, but if someone experienced says for example that on Wasp-os it's easy to write the program yourself, I can try to switch to it.

If nothing else you should update InfiniTime - there have been significant fixes since 1.2.0
https://github.com/InfiniTimeOrg/InfiniTime/releases

How easy it would be to write a timer app will depend on your skill level. There are already timers/alarms in both InifiniTime and WaspOS that will give you most of what you need.

Pomodoro is really cool!

it looks like there will be some pomodoro app available soon, but on wasp-os