Ventilation adapters

This is my first 3D model project where I have used CAD and made all the models myself so please be kind if the modeling is subpar. Then entire project is accessible on my GitHub with all the FreeCAD files, .step files and the print profile: https://github.com/michaelbrusegard/CAD_VentilationAdapters. I would be very happy for any Pull Request if someone with more CAD experience has improvements or any other tips etc. I am aware that tolerances are very bad for most of the models. This is because I was unaware that I need to add a 0.3mm tolerance for places where you need to insert something. In this case, this issue is mostly for putting in the fans. It is very hard to push in the fans, but I was able to do it for all the models I printed myself. Since the CAD files are available it should not be very hard to modify them with improved tolerances.For the booster fan model a standard 92mmx92mmx25mm is used. I ordered and used the Delta AUB0912H from AliExpress. For the in wall vent a la