Greetings - the easiest and safest way to bypass the temperature control of the freezer, refrigerator, or whatever you have is to take the existing thermostat out of the circuit. Thermostats in this type of equipment are typically a two wire “on-off” switch that switches based on temperature. So, using the Inkbird controller would allow you to simply plug your freezer into the “cooling” side of the controller, set the temperature and away you go. If your existing thermostat is NOT a two wire control, bypassing it while allowing the other components in the circuit to do their job will be complicated.
I did this to my fermentation chamber (previously a kegerator) with great success. However, I had no means of heating. So, I purchased some inexpensive components from my local hardware store and a reptile heater from Amazon for $12 and wired my new heater to the “heat” side of the Inkbird and now I have full and complete control of my fermentation’s from below freezing to in the 90’s if I choose.
The wiring scheme you’re proposing can, if you’re not very familiar with refrigeration and associated controls, cause serious issues with the system refrigeration and electrical components and could potentially cause a fire, short circuit, or irreparable damage. Just a word of caution.
Hope this information helps!
Good luck!