I went through a similar Journey a year ago. However my room is much smaller @ 13 x 15 . My list had a number of speakers already listed. Including Dynaudio Special Forty ( loved the Contour 20 much better Maybe used $3500). ATC SCM 11 or 19 , Proac Response D2 or D20R ( not sure if bookshelf) , Legacy Studio, Fritz Carrera BE. I also included Acoustic Ariel 5T, PMC IB1S Studio Monitors or the Twenty 5, Focal Electra 1008BE , Selah Tempesta. My goal was to replace an older (20 yrs) Sonus Faber Concertino . I was also looking for a great price on the SF Olympica 1 ( used) . Only heard a few of the speakers live when a used pair of Monitor Audio Platinum 2 became available locally . It has incredible highs and an outstanding firm base response. The base was so good I no longer needs the SUB for the music I play . I am shocked at how big they sound and fill the room . They soundstage is very wide. Literally blew the old SF's away - not surprisingly given the age and cost difference . I use a 36 watt Tube amp and maybe max at 11oclock on the pre without them being much too loud yet still sounding very clear . I thought I would need more power .
With a large room I think you will need to be much more selective . Even with a SUB it will be hard to fill the room . I know you are looking for a Bookshelf Speaker but there are some lovely and great sounding floor standers with a small footprint . Maybe a used Totem Forest Signature for a room that large.