My speakers don't "dissapear"

That combo should disappear nicely. I've heard it happen impressively with my own ears with the 400xi and Focal Profile series and decent Audioquest cables.

Are the speakers too close to the rear or side walls perhaps? Also, what kind of ICs and speaker cables used? Clean power is another consideration. Do you use/need power conditioning? What is the room like? Is it extremely dead acoustically perhaps?

"stereo and tv is diagonally set up"

From your description, short of a defect in speaker wiring or such (doubtful) this may be working against you the most compared to the norm.

Also, what's the distance between the speakers and the walls?

Burn in time may also be an issue with this equipment according to others here more knledgeable on this than I.

Excellent.

I'm finding when a system that should sound good doesn't, the placement within the room relative to walls is the first suspect and also the cheapest (though tricky) to fix.

I should have been more specific about this before tossing in other less likely possibilities into the frenzy as well, especially those that might still benefit but also add cost.

Yes, and also toeing in speakers so more sound reaches your ears directly would also clearly work against making the speakers "disappear".

Good news. Enjoy!