Hi,
If you still here I think the best solution is to build a bike yourself!
You choose the frame you like, front fork, groupset etc.
Then you have to assemble all parts also yourself.
Do not buy standard bike from massive bike producer, they all are the same and too commercialised.
When you build your bike ride heavy as much as you can before
you left for a long trip, then you will realized you need to change some parts, so do it.
Only after that you will know what is your bike.
I personally love titanium as best material for long and heavy travel.
So I build my bike myself since 15 years ago and travel with my bike in many countries.
Sometimes I use my bike in extremely heavy conditions.
Since the time I changed many components on my bike and
to the moment it is very different from the first bike.
If you like I can share my experience and I can help you
with components like frame, front fork, seat post,
stem, aerobar, handlebar made from titanium. And I know
how you can buy all titanium parts for a very good quality and price.
Good luck!