Dear oh dear,.... try thinking outside the square! Any fan-forced oven with a timer....jam something in the door and set it as low as possible. A probe thermometer may be useful for fine adjustment. In the dry season, just place you stuff on a tray in the shade. That has worked for thousands of years, so it will probably work now. How long do you think it will be between checks? A timer is not needed unless you are going away for a couple of days anyway. Yes, various foods take different times, but this is like saying you need a tablet when a desk-top will do the same job. The whole idea of self-sufficiency is NOT to rely on new-fangled, expensive, pieces of technology. Nor the technicians who service them. I had my last gas oven worked out to a tee even. Just set the thermostat halfway between 100c and zero, with the door slightly ajar. Never cooked tomatoes nor banana chips. Rather than try to do the lot in a 9-drawer machine, just do the ripest first. Lateral thinking people.
A rice cooker is a saucepan full of water, tended by a rice COOKER..........Not a device along side the Breville, the Mixmaster and the Hoo-Flung-Dung machine.
Technology should be your friend, not your master. It is the design of us Hoomans for betterment, not to be the over-riding be-all and end-all. God-forbid if we couldn't even grow our own vegetables without Thrive or Super-phosphate, vermiculite or even seed-raising mix.
As a hunter-gatherer I regularly stalk the aisle of supermarkets for over-ripe produce at discounted prices, to be de-hydrated. Mushrooms are a regular windfall. Mushroom chips I eat straight, but they also make the best soups, stews or whatever else, due to the intense flavour.
Don't be hijacked by the capitalist regime of false need, or you will ultimately pay top-dollar to keep up with the Jones' s.