Where are you located, Konrad? Maybe your best bet would be to solicit a paid consultant via this forum, someone local to you who's willing to come to your place and solve your problems first-hand.
It's not a business category you'll find in the Yellow Pages, but you never know: the expert adviser you need may be right down the street and a reader of this forum. Someone who could save you from throwing unnecessary money at the problem without first understanding what the problem actually is. Shotgunning in the dark can get expensive and frustrating.
X1 was indeed Cakewalk's most embarrassing product. After having long been first in line for every new version, I elected to skip X1. And X2, and X3. I would have stayed on 8.5 forever, but after my DAW was stolen and I had to start over from scratch, I crossed my fingers and took the plunge with SPlat. Short story: it's been a delight. Solid and mostly trouble-free, with most bugs being quickly addressed. Moving off X1 will undoubtedly resolve some of your software problems.
That said, it's entirely possible that at least some of your issues may be hardware-related. However, I wouldn't buy a new DAW until I
knew that was the case.