I am listening to a pair of refurbished Acoustic Research AR-2ax in my office, a similarly sized room to yours, essentially 6’ triangle. You could call them large bookcase, or compact 3 way.
They have level controls for both the tweeters and mids to balance their output in any space. I drive mine with a Luxman 10wpc tube amp. The 10" woofer produces full range without over-powering you when close. My prior Wharfedale 225’s 6.5" woofers needed a sub to avoid sounding small.
They sound so good, I restored a 2nd pair for my Garage/Shop system. I bought new level controls and new tweeters for that pair, and new grille cloth, everything is available for these.
A restored pair of AR-2ax, I would get the stands he shows them on also