I have done my drying/curing in mini-fridges and wine coolers exclusively since I started because a full-size unit is never gonna happen for me according to this house's business manager (i.e. my wife). With smaller units like this, it can definitely be done successfully, but yeah, one needs to make some adjustments versus a full size unit.
The two main issues are the limited amount of air volume in a mini-fridge/wine cooler, and the cooling mechanism. Using both mini-fridges and wine coolers, I have never had an issue getting rid of moisture--in fact, it is exactly the opposite. Because they hold such a small volume of air, and the cold plates get so cold causing moisture to condense and freeze on them, your product will dry too fast and have case hardening unless you have a humidifier in there to add humidity as needed. In my experiences, a heater/dehumidifier has never been needed in these small units--only a humidifier to add moisture as needed.
In a mini-fridge with a horizontal freezer compartment (what I started on), the act of constantly adding moisture will lead to the build up of an ice cake over the cooling elements since there is no defrost mechanism. This is not really a critical problem, just something to keep in mind. In a wine cooler (what I am using now), many have a vertical plate at the back, and a drainage channel underneath it that will lead to an evaporation pan above the compressor. But since you have to constantly add moisture to prevent case hardening, this might actually overpower the evaporation pan and cause it to overflow, thus, necessitating another adjustment. In my case, I just bypass the evaporation pan, and run a plastic tube to a container that I occasionally empty.
Also, with these mini-fridges or wine coolers, you do not need a full-size humidifier, indeed, those are probably even overkill for a full size fridge unit because a full-size humidifier is capable of humidifying ROOM-sized volumes of air. For a mini-fridge or wine cooler, a tiny/mini ultrasonic humidifier is enough, indeed, more than enough given the small air volume. I am talking about the size you might see as listed for "aromatherapy" or similar that might hold like just like 2-3 cups of water or less.
For my current setup, I am using a Tramontina 4.4 cubic foot Wine/Beverage cooler (model 80901/102) that I got at Sam's Club a few years back. I use the onboard thermostat on the fridge to control the temp, and monitor temp/humidity with a Raspberry Pi system that also controls a mini ultrasonic humidifier to add moisture. I like the Raspberry Pi system because it allows logging, but this is an extra level of complication since most folks have great success with the Inkbird temp and humidity controllers that are easy to just set-and-forget. I am not entirely happy with the onboard temperature control with the wine cooler because despite having a supposed degree level of precision (i.e. you dial it up/down in degree increments), the results are not linear. By this I mean that you dial up/down the temp by one degree, but the result is 3-4 degrees of difference. So I might eventually move temp control to the Raspberry Pi, too. If you go the Inkbird route, this would mean the temp controller, too.
