I've been riding a Titan for about 14-15 months at this point, meaning 2 winters and a COVID summer full of riding. I came from a Transition Sentinel, and I had a hard time figuring out which size to get in the Titan, but at 6'1, I was running a large Sentinel which was a full 15mm longer in reach than the Titan. Ultimately, after some back-and-forth with Michael at Banshee, I settled on the large with a 50mm stem, and it has been perfect. I honestly don't understand why you'd want to run drops longer than the 'short' 452mm unless you were on the XL (Banshee agreed with me on this thought), but I guess you can do as you wish for the sake of testing!
It's interesting that you're having trouble finding a comfortable climbing position, because I found it very easy. Perhaps it's because you've gone up in sizing too far - the shorter reach may have tempted you into a bigger bike if you didn't consider the stack height, and if your legs aren't long enough for the admittedly slightly long seat tube (IMO), you're likely running a steeper effective STA by having to keep your post slammed. I'm running a 170mm post, about 1.5" of post showing before the collar, and this bike is one of the more comfortable that I've used from a climbing perspective. The weight is the main drawback on that front, but I can drop the hammer no problem.
FWIW, I 100% agree with you on the stock X2, and mine was the supposedly slightly worse 2020 version. I couldn't get it to feel good (always dead), so bit the bullet on an EXT Storia and it's been a total game-changer for the bike. It left my old 2019 36 GRIP2 feeling otugunned, so I'm now running an Ohlins RXF36 m.2 at 170mm extension. The Ohlins has a longer A2C than Fox or Rockshox, so my bike is a bit slacker in STA and HA, and reach slightly shorter.