Looking for app: flexible routines

I will be recieving a gastric surgery somewhere in the future. After which, I am to follow a strict schedule for eating and drinking. I looked at a lot of routine apps, and tasker apps. But they all lack the flexibility I need. Or I am just missing it.

Why I need it: my life does not fit a daily or weekly strict schedule. It is quite dynamic when my day actually starts and varies month by month.

If I have to move the tasks or alarms manually every time, I know I won't be able to stick to it.

If I have to manage a massive list of routines for any possible starting time. I will probably overwhelm myself and abandon the schedule.

What I need:

• Able to set a day spanning routine, that can be started at any time.
• Have an alarm that can be snoozed, and will also push all next task with the same amount.
• Be able to trigger a task early, and push all next event forward by the same time.
• Have a buy-once option
• Nice to have: wearos support

I am about to investigate how to make this myself. But I would suspect someone already made this.

Thank you for reading, and your time.