I recommend using the Duplicator plugin.
Install it on your dev site and using Duplicator, create a backup/migration zip file.
Then on the new domain upload the zip file which contains all the dev site’s files and database/tables.
No need to install WordPress again on the new domain as the Duplicator zip file contains everything (core WP, theme and plugins).
It even contains a very easy to use setup function, where you enter the new domain and it does a find & replace to change the old domain for new in the database tables. Simples 🙂