I printed the enclosure, and it worked out well. There are slopes for easy printing without support, and everything went fine :

Some cleaning to do, but nothing problematic.

I added a second row of holes on the back :

Compared to the previous design, i added a thicker base for the bottom holes, so that those ones can also be closed using lids and gaskets, thus waterproofing the box if needs be.

For this version i did put a lot of holes, since i don't know yet what add-ons i'll be connecting to the box, and since it took 6 hours to print, i went all-in on openings, considering that those can be closed but not the other way.