I ended up with this solution instead:
as I wanted to meet the following requirements:
- possibility to create scheduled departures for regular activities (like various evening activities - morning departures gone with Covid19)
- possibility to have at least one ad-hoc upcomming planned departure, like shopping @ 14:30 today
- possibility to start now (and leave any time within 2hrs)
I have not yet implemented the dynamic runtime on the ad-hoc time based setting, but that should only require an input_number helper, currently I will rely on the default 2hr max automation.
Some kind of countdown timer would also be nice…
The concept will be put to test as the chill closes in, but for the last week or so it has got milder rather than colder so testing conditions are not going my way :-/