Sorry, I do not understand what you are saying ("3d configurators on game engine (play canvas)"?), but are your clients giving you models with wrong/inconsistent Normals? In that case, I think you should fix the models one by one and charge the clients for the extra time you had to put in.
If the normals are coming in flipped on those windows, then for sure that is a lot of manual labor having to go one by one, there is no way around that I think. You could give the clients a call and get a pipeline going where they send the models with the normals in the right direction from now on, that way they save money and you save time and tedious work.
If the houses are all the same, you could put it all on one collection, modify that one and just instance that collection all over the place and then if you want you could unlink them and make any one of them unique.