Hi,
I have read your exact requirements and also checked the Dropbox.
I will migrate your complete Magento 1 store to new version of Magento 2.3.1 so the complete database like customers, orders, products, categories, etc will be move over there.
Query: Do you want only migration to 2.3.1 with default Magento theme or any theme setup and customization also?
I have +8 years of experience in Magento and also have +5 years of experience as a Linux Administrator.
Regards
Karuna S.