I think you've identified the problem here, you're starting out with a parameter that will prevent you from being happy.

No one bike can do everything. get a real race bike (not vintage steel, something recent and light, carbon or alumium) for your fast unloaded weekend rides and keep the LHT for loaded touring (or don't, if it doesn't fit you).

Your CX bike was probably closest to a do-everything-sort-of-ok compromise bike, the LHT is definitely purpose built for load hauling, and a race bike would be best for faster fun road riding without carrying stuff. Why have one bike that is bad at everything when you can have two that are good at what they are made for?