A spare fridge is the usual answer and the easiest one. Nothing to modify — the hook hangs from a shelf rail or a bar, and everything else happens in the app.
The fridge you use every day works too. It's opened often, so conditions move around more than in a spare one — the hook accounts for that, so you're not guessing what those swings did.
A cellar or an unheated garage is how this was done long before fridges, and in the right season it still is. What's different now is that you can see what the air is doing instead of guessing. Anywhere that isn't sealed, hang the protective net as well — keep it clear of the meat and clear of the lower part of the hook, or it will lean on the weight reading.
A wine fridge holds cold well and moves very little air. Hanging helps. Crowding it doesn't.
Set up any of these and you have what people mean by a dry aging chamber. It isn't a machine — it's a cold space with something hanging in it, and something measuring.