if you are trying to warm up the whole space then any electric heater will basically cost the same. Electric heaters are 100% efficient but not always the smart way to heat.
IR heaters will heat the objects they are pointed at.
If you want to heat up the whole room and air etc then oil filled, convection etc etc will all be much of a muchness. The oil filled has a heat storage capability yes, but you still need to use energy to heat that storage based on it’s shc.
Obviously IR have their drawbacks too as when you move out of the line of site you get cold. But you should be able to get a nice warm feeling for a lot less £ than trying to heat a poorly insulated, cold and possibly damp garage by convection.