nice

3/3
In blender in sculpt mode, smooth all of the surfaces that are supposed to be flat. You can also try to add or remove matter if needed.
In edit mode, you can make the roof/missing walls or part of the model :
select 3 or more verticles (point) at corners of your roof with SHIFT and press F.
The new surface can be oriented badly, so be sure that it is facing the same as your model others triangles
See this for viewing and flipping those new faces https://youtu.be/lw0_yWHKuCE?t=8
Re-orient the model to its default position with "N"

Import the model back in your software and tell him to create new UV !

Keep doing photogrammetry, it's a cool activity

2/3

I removed useless or too private things from my room, and placed post-it and blue-tack on all corners of flat surfaces. (the corners for the roof and walls are really important !)
As your room has straights walls, it's easy in blender to make them.
To do that, you need the option to import a model in your photogrammetry software.
Reduce polycount to something less than 3 000 000 (because of bad performance in VR and slow edit in blender).
Import the model in blender.
Select it and press "N"
Take a photo of how your model is oriented by default.

Not bad at all !
Not an expert (the opposite) but I can give you some tips : when doing photogrammetry in VR, the most important is textures and not poly count. I have uploaded some models with 4 000 000 polygons and they run really poorly, and they didn't even have good textures.

Because of bad performance, steamvr home SuperSampling will be reduce and it won't look good/be smooth.

At the moment, I'm doing the same as you, my room in vr. Not yet uploaded in the workshop but on sketchfab : https://sketchfab.com/3d-models/bedroom-with-pc-11d531fcfe794271b04c643214f20b11
It runs really really good in steamVR home (2 000 000 poly, 8 8k textures)

1/2

Very nice and colorful. Thank you for making your bed.