Blender 4.2 LTS is the minimum. I check it with an automated suite in 4.2 and in 5.2, the versions I use. Other versions should work; the day I test one, I will say so here.

Select it and press Make It Cardboard! Pick one of four ways: a shell (one sheet of board over the surface, best for boxes and packaging), laser-cut layers (stacked plates, the contour-model look), a glued mosaic (flat pieces of board, flush or with a seam round each) or a kit card (flat profiles slotted together, like flat-pack animals). Nothing is destructive: your original is kept hidden, thickness is a modifier, holes and slots are Booleans you can delete.

Yes, as an advanced base you then adjust. Pick a city style (Manhattan, Madrid, Barcelona, Paris, Venice, a medieval town, an industrial port and more) and press one button: streets with crossings and traffic lights, houses, civic buildings, parks, pools, bus parks, landmarks and a belt of woodland, all in board and all editable. A few clicks of adjustment and your diorama is done.

No. Sheets are box-projected, edges get their own coordinates, tape and stickers carry their own UVs. A set of realistic cardboard looks ships with it; you can still point Material from Images at your own folder.

Yes. Save as Asset keeps anything you model in your library with its themes and a picture; Export Pack writes your pieces as a .zip that anyone with the add-on imports with Import Pack. A pack holds pieces and pictures only, never code.

Yes to both. Every material is a plain Principled material. Bake and Export writes a GLB, or an FBX for Unreal or Unity with collision boxes and levels of detail.

Yes: renders, animations and exported models you make with it are yours. Updates and support are included for good, with no support period and no renewal fee.

No AI inside: it is geometry and node code that runs offline. It goes online only when you press Download in A real place, to fetch the map you asked for.