So it does just use the file name but as a software developer, I would have expected it to be LightBurn and after a file is loaded, LightBurn - filename. It is the application titlebar after all. Probably fine in reality since the LightBurn icon is identifiable in the launchbar area but still, it would be far better to have the file name concatenated to the actual application name. $0.02
I don’t have a solution for you, but just want to say I had the same problem as you. Running Lubuntu on a MiniPC with an old monitor at 1024x768. My Lightburn also opened much bigger than the screen.
Another problem I had was that the righthand windows kept resizing themselves to the full width of the screen so the work area was not visible. I don’t know how it got fixed but after a few times resizing windows and restarting Lightburn, the windows stayed the way they should be.