Moving from overseas to Japan with long term work visa – 14 days to find fixed address – Work starting January

Hi,
I'll be moving to Japan with a long term work visa this December.
I've been reading about the 14 days to notify city hall of fixed address and I wanted to see if anyone could please kindly clarify a few things for me.

Do I need to go to city hall within the 14 days to sign in even if I haven't found any long term apartment?
Or, do I mark down my temporary address (hotel, hostel, guesthouse) first, then apartment-hunt, lock something down, then notify my fixed address?
(I understand the 90 day rule to fully lock down an apartment)

Also, I will be moving to Japan early December starting work January 5, so perhaps there are some issues that might arise if I haven't got a fixed address or even a share-house address?

Thank you kindly for your help.
Cheers!