Hi RogerJNeilson,
welcome to our forum!
The game officially runs on Windows only. I am happy that it also started in Parallels but it wasnt tested for that. Every game is based on different engine so the fact that other Matrix games work doesn't guarantee that another ones will work as well.
On the other hand, it seems like the problem is resolution only. If you are able to find file initialSettings.config (on Windows it is always located here C:\ProgramData\Kubat Software\Aggressors Ancient Rome\) there is element called "videoMode". Try to tweak that value per your own screen resolution. Once you have this correctly tweaked (so the main menu is in the middle of the screen) you might also increase the uiScale value.
Let me know if that worked.
It might be even easier if you join our
Discord channel and if I am online we can try it together.
Pavel