More furniture advice

[FromTheFirstOldFashionedWeWereCursed]

Like the OP on the other thread, I’m trying to decide whether to buy two “statement” chairs (probably matching each other but not matching the sofa) or something else to go on the left of this photo. The lines on the left are steps down into the dining room which has huge French windows (the only source of light for this room).

Is the room already set up so you have a sense of 1) what would fit and 2) whether you actually need another chair?

Well I have statement chairs so I'll say yes

is this drawn to scale? I think chairs will look very clumpy there. If you want statement chairs t makes more sense to create a statement chairs curbed opposite the piano.
for the corner next to the sofa I’d choose a nice floor lamp and a basket for throws /cushions.

I would zone the room more. Move the sofa left then the bookcase behind the sofa against the rightside wall. One oversize armchair bottom left corner at an angle facing in, small side table to the right with lamp over. Coffee table somewhere in front of the big sofa. I don't think there's room for two armchairs. You don't want to block the French windows off. It also looks a bit regimented as it is.

I'd be choosing comfort over aesthetics as part of the plan. One thing I have learned from airbnb places is that the two rarely come together.