You're right there.
I've looked at the likes of Mason (lovely bikes and the Ti frame looks the nuts

) and a few others, as well as going custom (my dream bike was a Roberts of Croydon

, but unfortunately the are in hiatus and may not return).
You need to workout what your main uses will be and buy accordingly. That's why I went with the Cube in the end. I have a hybrid, flat bar, 3 by and a gravel drop bar, 2 by bike. The Cube e-bike fit in with what I was looking for at the time.
You seem to be wanting an endurance / climbing bike, but it's not my money so buy whatever takes your fancy.
1 by systems are great if you know exactly what you'll be doing, but otherwise are too limiting IMO. I've got a big cassette on the rear by using a hanger extender. Once set correctly it will work fine. I'm running a 52/36 with an 11-42 xt cassette. I get the odd mis-shift but it is very rare and usually down to my poor setup. I can climb most of what I encounter where I live on this, except the silly 17% stuff just down the road.
Happy hunting for your new bike. It takes me ages to decide to actually buy once I chosen what I want. I always seem to want the next best/newest/inovative thing to come along. I hope you are quicker to decide than I.