Freezer compressors are sized for simply keeping the contents cold of their well insulated box. Trying to run an external load will likely overload it’s capacity.
25' of copper would not be nearly enough to do the whole job but it would lower the temp some, and over time it would lower the temperature relatively safely ( safe against freezing the lines ) and likely consistently unless the tub is continuously filled with mammals or in sunlight or sunlight-warmed air.