It actually is desirable, as it kills any comb-filtering due to front wall reflections; it also dramatically reduces the head-in-a-vise effect, as there is no longer a 'balance' to deal with rear-wave reflected sound vs. direct sound.
Yes, it significantly alters the perceived soundstage, but once you get used to it, it is a more satisfying listen, and the sweet spot is wider, enough for at least two people.
Absorption is THE game for multichannel setups, as dialog clarity of good instrument localization is important.
For instance, Atmos music will be one ugly smear without absorbing reflections. Immersive positional algorithms assume monopole speakers.
My room is completely treated, my front wall is covered edge to edge with absorption, and the first 14' is mostly absorption. Atmos music and movies are a treat to hear.
For the OP, yeah, that's a crazy small room, absorption on the front wall and the first 4' of sidewalls would be necessary, as would hanging a thick rug on the back wall to tame reflections from there. See this for an example:
https://www.martinloganowners.com/threads/media-room-–-quad-ml-sub-setup.17591/