As you told , you can create microflow which will update product price with respect to date and time.
Create a scheduled event, call your microflow , configure your scheduled event in such a way that it will get executed every early morning.
Your microflow should check for the date and time, if your current date matches with expected date, then update price. if not skip it.
Take a look at the below module ’Microflow Scheduled Event Manager’ where the scheduler can be configured in UI
Hope it helps!!!