I've been using Godot so it won't compare fully but, in Godot you have the Camera Node (Class/Object) that has a zoom option, and then in the Project Settings menus there are more options for how the Game Window is rendered, scaled and zoomed to the screen. You may have tried to look for this kind option in Unity, but I hope it helps. If you can't find it in the UI, maybe there are scriptable options that can be accessed as well.