Have you considered one of those small socket heaters? https://www.amazon.com/heater-Programmable-Adjustable-Thermostat-Display/dp/B07DCKFJLM/ref=mp_s_a_1_12?keywords=mini+heater&qid=1675080081&sr=8-12

Something like this? They're fairly affordable, have timers and don't use up that much electricity, would be perfect for a small space