Designing an globally distributed restful API that writes to databases

I am currently designing a distributed restful API service that takes request from client side and writes the payload information into multiple database located in different geographical regions. The estimated QPS is ~100k. Data won't be read immediately after it has been written. What are some design considerations in designing such service?

I also have a few specific questions:

1. There will be collocated services consuming data from the databases in their respective data center, should my service still writes all data to all databases? Or should I only write data specific to that region to its local database?

2. If data recency is a concern (i.e. data that's being written will be read very soon), what architectural changes should I consider?