The quickest way to burn out is to cook, sell, deliver and do admin all at once, all the time. A simple weekly shape fixes most of it.
Block your week into prep, service, selling and admin — even rough blocks help.
Batch similar tasks (all your labelling at once, all your admin at once).
Leave slack for the unexpected order or the oven that misbehaves.
Each week, note what overran and adjust the blocks.