Looking for alternatives to Google Tasks

Hello,

I recently migrated from Gmail / Google Calendar to Proton, and while I find it to be a perfect alternative to both with great UX, it does not provide a suitable alternative to Google Tasks.

I know Proton Calendar has yet to introduce tasks/reminders and that users usually advice using alternative apps just for this need, but I have yet to find an alternative that exposes an ICS calendar I can import in order for tasks to show up directly in my calendar.

So I’m open to your suggestions! For the other requirements, I’m looking for:
- recurrent tasks (like every day, every first Saturday of the month, every 6 months, etc.)
- either an Android app or a PWA for adding tasks
- preferably self-hosted, but I’m okay if not

Thanks!