Most don’t work very well in low temperatures so be carful which one you choose as the figures they quote can be for the room at 25c 80%.
I have a cheap one in my pin room but I also have a heater that keeps it above 14c so works fine, I also have a coupe of DriEaz expensive LGR dehumidifiers that are really good but they cost about £1400 each!
A desiccant type dehumidifier will work better in lower temperatures so if you are not putting heating on that will be the better type for you.
Cant recommend any though as have not used that type.
They will add heat but nothing like a heater.
I run both an oil filled radiator and a dehumidifier, set at 50% humidity (therefore it’s not on all the time). I have a small Games Room in my external insulated garage.
The problem I can see having just a dehumidifier is that it will be on all the time and is not really to be used solely for heating.
I would go both or use a heater and then maybe a couple desiccant dehumidifiers. How well insulated is it?