A THREAD FOR NEWCOMERS!

I use HoMM3 HD 5.5 Launcher. My computer has an RTX 4090 with a 50" 4K screen. When playing, my eyes start to hurt. I decided to check the frame rate, and it turned out to be between 7 and 200. Moreover, when the map isn't moving, it drops to 7 frames per second. In the Nvidia control panel, you can force a limit to remove excessive frame rates. Does anyone know how to set a limit on the minimum frame rate? I'm sure the strain on my eyes and head comes from the moments with low FPS. By the way, it's impossible to play like this.
Thank you in advance for any possible advice.