Yeah adding buttons to the top of a detail page, or a second form page for an admin action are unnecessarily hard. I've had to do both a number of times in the last few months, and referring back to an existing implementation is the only way I remember how to do it.
Those two particular customisations should be a lot easier to do, and it might even be something I'll look to implement as a 3rd party library or directly within Django.
With the ORM though there is usually a good reason for why the hard things are hard, and writing your own SQL where needed adds very little friction.
With the admin adding a button to kick off some task should be trivially easy, but for whatever reason involves either using all sorts of terrible hacks that make the codebase completely unreadable, or else creating an entire second admin. That doesn't feel right.