This is the DF-3 Fighter. After the success of the P-51, the designers at DoggyDev air and space used it as the basis for their newest, most advanced fighter that would enter service in 1941 soon after Pearl Harbor. Armed with 6 .50 cal machine guns just like the P-51. It will rip most targets air and ground to shreds. They have also put together a version for the navy and another version for the United States Army Air Force (USAAF).
The naval version saw service alongside the SBD Dauntless during Midway.

So I originally created this for a building challenge and the fictional country this plane serves under for it is Iosia which is a fictional counterpart for the United States. They forgot to repaint them after ordering so the USAAF logo is still there.

Link to naval version: https://www.simpleplanes.com/a/5L4esf/DF-3-TB-Fictional-US-WWII-Naval-Fighter

Link to air to ground version:
https://www.simpleplanes.com/a/4h5qC4/DF-3-Fictional-US-WWII-Dive-Bomber-Fighter