Recently had new extra secure garage door fitted and two new cellar windows. As the garage is below ground a drain and pump have been added. The cellar has been plastered, waiting to be painted and then old kitchen units fitted. No plans for a kitchen down there .... just use for storing tools.
The builders are coming today to do a quote for plastering the garage and a lick of paint. The exterior of the house needs repainting on three sides so that's another quote. After that replace three interior doors and get glass fitted to two of them!
Not forgetting the lighting in the cellar needs refitting, plus four new electrical sockets are needed.
(Probably a daft question as I read an article somewhere that it wasn't safe to use a fridge/freezer in a garage, cellar or shed!!! Advice please 😌).
Oh, before I forget we need the interior repainted ..... might do that myself otherwise we might have to move everything out of each room as the decorators go through each room. Doing it ourselves we can just move the furniture from one side to the other as we go along).

On 22nd July we had been living in Hungary for five years with four of those in our house. 😁

personally I wouldn't bother plastering any non-living space, it's a waste of money imo, but that's just me

As an alternative to plastering and painting the garage you could just paint the blockwork (or brick work) which will get the place much brighter and save the expense of plastering.

No problem with putting fridges or freezers in sheds, garages or cellars
except that
sheds can get v. hot in the summer which will/can make fridges and freezers work overtime, the same applies to some garages. Some fridges will automatically switch off if the temp. goes below 5 deg. Some units don't like the wide temp. variations you can get in sheds and garages. Some freezers actually state 'suitable for use in a garage' on the instructions. Some sheds, garages or cellars can be prone to condensation which will hasten the inevitable rusting of the units. On balance garages (brick or block built with a proper roof) are better than the typical garden shed and for an integral garage or basement garage then no problems.

We have both our large freezers in the cellar on 3" blocks (because that is where our water system is and the occasional failure resulted in a 'bit' of a flood). We have never had a problem with this location.