You have received a lot of good advice, although if you take all of it you’ll have to start over. I would go slow. I would start with speaker placement and modest room treatments- I don’t think you have to rebuild the room to get decent improvement. Then I would consider what you think you are missing and how you can get there- starting with speakers. You have great speakers IF you like the B&W sound, as many do. If the speakers are not voiced to your taste, however, you are not likely to ever be satisfied and I’d make sure you have that right first
if you do, the most obvious component upgrade is your DAC. Listen to as many as you can and go from there- with what you like. Be careful of well intentioned advice because components or brands that someone else chose may be perfect for them but not be at all for you. Take advantage of having a good dealer nearby
dont expect too much as you make changes, especially after speakerd
most improvement is incremental not a sea change at least in my experience.
good luck and enjoy