Yes, after many attempts, I managed to solve it.
In my case, the problem was caused by a type of cache in the game's Shaders.
For some reason I couldn't identify, even after uninstalling the game or manually removing the folders, the Shaders weren't loading correctly, keeping my FPS frozen.
To solve it, I reverted to the latest NVDIA driver and forced the card's Shaders to be reset.
With that, I started other newer games, the Shaders were reloaded, and when I opened BF6 again, it took a long time to load, and the FPS was unlocked, becoming even a little better than what I had before.
But I ended up tweaking almost every possible option.
I hope these actions help you too.