Sorry you have not been able to locate a breeder near you, but hope you will be able to as you have plenty of time. But you may have to travel a reasonable distance from your home to get an approved breeder. There are breeders on YT that are totally reliable and many here do buy from them on reputation only without a visit.
Yes it is usual and expected for breeders to ask for a deposit to secure the pup, but one just has to know the breeder is ok first
Certainly it is not usual to pay the full cost up front.
It is great that you are taking such care to find the right breeder and not get caught buying from a greeder or puppy mill. Good luck in your search and research