Indeed, I have the impression that we have lost ourselves in the battle.
I have to make a record of a complete installation as a finished product (provided by our subcontractors) All the files received were in parasolid, so no surface. The only elements I have in surface are the metal frames, files that I can't convert into volume because carpenters don't work in volume. (if you have a solution on this subject, I'm interested, but I'll probably start another discussion on this subject)
In the end, I have a general assembly that is more than 1 GB that I can't save and I haven't re-inserted all the subassemblies yet.
This assembly will ultimately have to be sent to our customer.
I'm going to try the solution of "froussel" and "olivier42" which seems to me the most suitable.
To lighten the assembly, indeed, you have to "FIX" all the elements (Assemblies, Sub-assemblies, parts). By doing this operation, all the constraints are put in "partial deletion" and SW does not have to rebuild them, nor load or save them => we gain a few KB
Creating as many subassemblies as possible in the master assembly also helps to reduce the size of the assembly.
According to the information I was able to get too, you have to do the minimum of "configuration" and favor the "Display States".
I'm going to put all these methods into practice and cross my fingers that it works. I will keep you posted, thank you.