With a bit of following guides you can install and play all the DLCs (except for a small section of the robot one that needs completing in flat mode or using cheats) and most mods available for the flat version.
Ive finished the Fallout4VR main storyline and played around totaling over 250 hours ingame.
I played mostly seated using steamvr advanced settings for “height regulation”, as a comparison ive played Fallout76 (same engine, similar gameplay) through Vorpx and its cool but being able to aim by pointing a controller in Fallout4vr makes the game so much more enjoyable IMO.