Soundstage is all about room interaction (wall reflections). It is important to have even dispersion as you get off axis so the reflections don’t color the tonal balance of the speaker.
For $2000 used you can get a pair of Revel F208. They measure exceptionally well and throw a huge sound stage and can play real loud. The bass could use a sub for my tastes but a slightly high bass roll off is their only flaw in their price range. They put a lot of speakers costing a lot more to shame. There are a few pairs on audio mart in your price range.