"One thing is for sure though. You do not have a freon leak. (Because freon is a DuPont trademark for refrigerant that has become a dirty word and they abandoned many years ago)"
That's not in one iota correct. I purchase thousands of pounds of recycled "Freon" 22 and "Freon" 502 yearly from Dupont. The word "Freon" is stenciled on the tanks right from DuPont. I have a machine, certified yearly by the EPA that purifies 2000 pounds of Dupont "Freon" 22 and 502 at a time and brings it to ARA standards within 24 hours. For re-use. Where you are confused, is certain types of "Freon" made by Dupont as well as others, like Genetron, are ozone depleting and those refrigerants are phased out or are in the process of being phased out. The word "Freon" is like the word gasoline and the word "Freon" is still used. The OPs freezer has R-134A in it. The box was manufactured after the EPA stopped the producing of R-12. If the R-134A is made by Dupont it's called Suva.
OP. The coil isn't dirty because it's in the jacket of the freezer. If the lid gasket is good and sealing right and your not looking at your fermenting beer every hour, good. Now, if the compressor is running and not cycling on the overload. In your picture you will notice a bullet shaped device with a very small tube coming out of one end and two tubes brazed in the oposite end. It appears as if the very small tube is bent, right where it is attached to the bullet thing. The bullet thing is the liquid filter. The small tube is the metering device. If the tube is kinked, it can choke down the refrigerant going into the evaporator. But, here's what I think has happened. The liquid filter is partially blocked. It has a screen in one end and there is silica inside of the bullet. The silca absorbs moisture from the refrigerant. Running a freezer at temps of 30-50 F never allows the compressor to operate at the pressure it was designed for. The high pressure liquid going through the filter packs the silica, until it hardens almost like concrete. The flow of liquid is reduced. Thus, cooling is reduced. If the compressor is running and not cycling off and on and if the frost line in the freezer doesn't change, the filter is blocked or the capillary tube is kinked. If the frost line dimminshes. You have a leak. The red/orange thing is where the factory put in the refrigerant. In any case, the compressor motor will overheat and fail. The compressor is suction gas cooled and since the freezer isn't cold. The compressor motor will over heat. Eventually, burning out the start relay and or the motor. I mentioned in other posts, that the family Maytag, is in no way, shape or form, a fermenting chamber. It's a meat pop freezer and designed as such. A Fermenting chamber is designed much differently, than a 200 dollar freezer bought from Sears. The problem with running a freezer at high temp is that the compressor is always working during a high heat load. It never has a chance to run long enough to pull down the load and reach the temp and pressure it was designed for. The more heat it has to remove, the higher the temp and pressure of the refrigerant. Sometimes the bullet thing will be warm to the touch if it's blocked. If none of things I mentioned are causing the problem, then the compressor is worn out and not pumping as it should.