How to stretch 4:3 Aspect Ratio/Resolution

Hi,

I purchased the game through Steam, and I know that this game has been abandoned by its devs like I think its been 3+(?) years since the last update.

But do we have here any options or ways to stretch out the 4:3 aspect ratio? Black bars is annoying. I just want to play the game in full display of my monitor.

This was my concern too on Apex Legends but they won't do anything about it.

Why do they have to lock the aspect ratio in certain resolutions? I've tried Googling but none of them provide a concrete solution with outcome.

My monitor full res is 1680x1050 and I have my display res at 1400x1050.

Thanks!