Do not interrupt the supply as an improvised energy-saving method. The appliance is intended to regulate its own operation while maintaining appropriate frozen storage.
What the observation tells you
A household timer can allow repeated warming and may be unsuitable for the appliance's electrical requirements. A hard-looking package in the morning cannot establish that all contents remained within the intended conditions. This is different from a manufacturer-designed control mode.
A useful next step
Use the recommended settings and permitted energy-saving practices such as clear ventilation and sensible door use. Ask a qualified professional about unusual electrical arrangements rather than cycling the freezer on a schedule.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.