Here's what I would do.
In general :
Start by excluding the DPoLs, excluding the electronics and associated gear, and considering just the room.
With no electronics functioning, is the room an acoustically pleasant space ? Invite friends over and get them to talk; carrying on two separate but simultaneous conversations in this one space should be effortless and non-fatiguing for all concerned.
Once alone, pick up a book; is this room a nice place to read ? Can you concentrate ? (I find this "test" most revealing).
Does your dog seem at ease in this room ?
To me all of the above should be part of what the French would call normal "savoir vivre", but it is not, and I am always shocked to learn that friends of mine endure acoustically horrible home environments.
More specifically :
From the photo of your room there seems to be adequate space, however the many hard, parallel surfaces are likely to propagate echoes (bare parquet floor, bare walls, window off to the right, bare ceiling... At this point, that big, woolly dog is probably the most effective part of your system!). The surface treatments of your room are typical of those found in certain regions, often having a very warm climate, or, in other cases, of the residences of people who are most concerned with ease of maintenance (ceramic tile flooring is a favorite of these folks...). There are reasons why slaughterhouses and morgues have tile flooring, and its got nothing to do with acoustics. Do you sing in the shower ?
In fact, the photo of your room reminds me of the corporate restaurant at the place where I work; I'm not at all exaggerating when I say the acoustics of this place result in indigestion, and are problematic to the extent that everyone complains, but the room is easy to keep clean.
Assuming fixed dimensional geometry, the optimization of an overly live or dead room can be accomplished to a great extent by adding/subtracting normal furnishings and surface treatments; that is to say, without resorting to expensive "official" audiophile-blessed room treatments.
You may also want to consider adopting a few really fluffy feline friends for that nice big dog.
How to short-circuit evolution: Enshrine mediocrity.