Many thanks to @Keet and @Xlance for taking the time to test the plugin and offer their recommendations.
I ask for their forgiveness for not being able to fulfill all their wishes.
That's all I could do for now.

Modeller3D version 1.2
Here are some news in this version:

• Improved movement around the object. Now it can be seen even from bottom.
• Improved Undo/Redo functionality when using the Ctrl+Z (Undo) and Ctrl+Y (Redo) keys
• Improved the movement of the selection using the right mouse button. It now follows the direction of the axes.
• Change the selection color to red for all selected items.
• Added floor grids and 3D axes similar to those in Blender. I set their orientation to the natural mode (Z vertical). This might confuse some people.
• Fixed how it works in full-screen mode.
• Fixed the flickering that occurred when selecting with the rectangle tool.
• Added Select All button (Ctrl+A) to select all points/edges/faces at once.
• Improved calculations and appearance (texture) of the torus and partial torus (bent cylinder).
• Added translations for 17 languages. AI help and a lot of manual work on my part.

Don't be fooled by the fact that it looks like Blender. It's much less powerful than Blender.
What I think it does have going for it, though, is that it offers 10+ customizable shapes that you can use as a starting point for modeling.

Now I think I can go back to the other plugins, especially the Roof Generator.
Hope you have fun with this plugin.

Also available on SourceForge and PluginManager.