Sorry OP - this seems very, very unbalanced: a high dollar, highly resolving upstream, paired with $900 metal dome tweeter 2-way bookshelf speakers. The Fire XLR alone lists at $3,500 / 1m. I think a lot of folks would’ve predicted the issues you’re having.
Obviously, you’ve got a lot advice to fix that imbalance. What you have, would be a great upstream for a lot of nice speakers.
On to cables - as others have also mentioned, the Fire is not exactly a relaxed sounding cable. It’s a cable I love, but it’s a little bit more aggressive than even other silver cables in the AQ line. I find my 1st gen Wild Blue Yonders are a little warmer and more relaxed than Fire. The Fire’s predecessor Sky (also 1st gen in my case) was also certainly warmer. The Wind is not the right move - it’s overall similar in tonality to Fire, but lacks the latter’s bass impact and body. And the WEL Signature sounds very much like an extension of the Fire. In fact the Fire sounds like like a WEL Junior. I’ve had both RCA and XLR pairs of all these cables. I’m not sure if later versions of Wild and Sky carry forward the 1st versions’ warmth, but those and the very limited "Horizon" model are worth looking at when they come up used. Quite honestly the v1 Wilds are probably my favorite. The copper cables (I had Colorado RCA and XLR) are a LOT warmer, at the sacrifice of some resolution.