P.S. I know Macs are nice, but please I'm constrained to only buy non-Mac freezers. For reasons.
https://www.homedepot.com/p/Magic-Chef-3-5-cu-ft-Chest-Freez...
In addition to the M1, I suggest getting a summit brand under the counter frezer, such as:
https://www.summitappliance.com/catalog/model/SCFF532D
They come in different widths, and are designed for built-in installation. You didn't say how wide the closet is.
Anyway, their trackpad and display ppi are terrible, and they're incompatible with asahi out of the box (leakage could result).
Using a USB-C to serial dongle, attach a thermocoupler to the mac. Remove the cooling fan assemblies from both devices, and place the mac fan where the fridge fan was. (You may need to run extension cables.). Place the processor as close to the condenser coils as possible. We're using the mac's temperature control logic to decide when to cool the fridge coils.
Now that you've done that, purchase an IFTT compatible smart outlet, and plug the fridge into it. Write a zsh script that polls the thermocoupler and powers the fridge on and off accordingly.
I'm assuming your closet only has one free power outlet. The M1 idles efficiently, so go ahead and plug it into the smart outlet too. It should be able to charge while the fridge is running. If you have a second outlet, consider getting a deal on an old intel macbook. They have bigger fans, and the battery life won't matter.
Anyway, that's it. It's pretty simple once it's working, and, with this setup, I guarantee you that your asahi won't freeze.