Heating, garage, frost protection

Good day forum members, I would like to hear your opinions and recommendations on how I can keep my garage frost-free. I am from Lower Saxony. The garage is about 30 sqm. 17.5 cm aerated concrete and brick cladding outside. The roof is a normal flat roof without insulation. Heating with a gas heater or wood is out of the question as I would prefer to heat safely with electricity, especially if there is ever a party in the garage. I am now considering whether to hang a fan heater or convector on the wall. Is 2 kW sufficient? Or do you have another idea?

I only say expensive fun and 2 kW are not enough.

Why does a garage have to be kept frost-free; there are frost-proof water extraction points.

There is nothing against dry cold, just ventilate well and that's it.

I actually consider heating to be rather counterproductive...

There will probably only be a wood stove left. Electric 2 kW is not enough and 3 kW is not enough either. I "unfortunately" know this from experience during construction, our garage is similar, but our walls have an insulation layer behind the bricks. With the gas heater, you bring too much moisture into the room.