I've tried a few Android calendar apps but I have found none that offered what I'm looking for: an easy way to reschedule undone tasks to the following day. Ideally, that should be done with a simple click.
I'm using Business Calendar (actually the paid "Pro" version) as my favorite calendar app – which I can recommend for many reasons. But sticking to your requirements here, the outstanding feature is to copy/move events via simple drag-and-drop:
As the screenshot shows: in the calendar view (no matter whether daily/weekly/whatever), tap the "hand symbol" marked ① in the screenshot, then move your item by holding it and moving it. When you release it, that leads to ② to select the action. Make your choice, done.
Try Calengoo. Great app. I have been using it for two years. Links to Google Tasks. But you modify the task within Calengoo. A simple click on the Tasks then on the task you want to amend and then click on the due date and change it to next day on the calendar. Really quick to do, unless of course you have a hundred!