I cant offer any help other than to say yes it makes sense and wow!
Nothing surprises me with new builds, my lad is going through something similar at the moment with about 20 rather large problems, one being they didn’t seal the bath properly and the water has gone down the back, rotted the floor boards and now eating its way under the dividing wall and rotting the bedroom wall behind the bed. Quite astonishing when my lad removed the bath panel to find that the centre bath support wasnt even screwed down to touch the floor. The chap that came out to re-seal it only chopped out a small section and then used a different coloured sealer. You really couldnt believe the levels of bodgery ive seen over the last few months. If i was to achieve the same level of care in my profession I wouldnt have a pot to piss in.
Hope you get it all sorted