You’re welcome, Adam!
I only tested for about half an hour (including the import of the .dae file), it remains to look for addons for Blender that automatically group/separate each element and test them.
And in SketchUp, as I tested, it will probably work, but it requires a lot of time.
Or maybe I will find another option.
addon DAE Clean
But the modeling of the ‘Maritime Youth House’ is more interesting and there is still a lot of work. 