For 1-1 meeting links, I can select "saved availability" and have zcal auto-fill when during my regular hours I am available based on my linked calendars. For meeting polls this used to work, but does not work any longer - there is no option to use "saved availability" or even custom availability. Instead I have to manually select every single time slot that I am available from an overview.

Since this used to work, I'm assuming this is a bug.