How can I provision a persistent array of int in flash memory and access it as an array of int from mbed C++?

Are you sure?
I can not test it because I do not have this board but both tools (Online compiler and Mbed Studio) can successfully compile program for this board, with bare metal profile.

And the FlashIAP can be probably added via Mbed_app.json file.

Save data on Nucleo F334R8 when powered by battery

BR, Jan