Air resistance will surprise you, and some watts will be necessary to reach 98km/h 

Here are my current tools:

Strava(subscriber) has a great route generation tool on mobile.
Strava have their heatmap, all tracks/roads people went to. A gold mine.

But then I send them to Komoot, for review/rework.
Komoot has precises terrain info and types. eg: avoid main roads, cobbles, or maximize single tracks for MTB(but manual), etc.
And start to have many points of interest referenced by the community.
If they had the quick finger mapping of Strava, I would just ditch out Strava.

I then use the Karoo 2 to record my rides and navigation.
After using the Wahoo Bolt for a few years.
Karoo has a neater navigation, touchscreen, real colors.

Unfortunately they just compete with other bike computers.
Same poor in-ride interface, with ungraphical pages with numbers.
They could do real breakthrough interfaces with such hardware.
It is Android below, we are in 2021...
It has only ~7h autonomy, with bluetooth off and minimal lightning to be visible a sunny day.

It has some other quirks:
rerouting is pitiful
the karoo connects to wifi, but you need to go through an odd web page to load a track
the powermeter is lost when you pause

BUT... I love it.
Their support is amazing.
For instance they are currently fixing the power meter issue, and I'm sure it will come soon in one of their regular update.

Why not put a handlebar on any of the cross country bike we've seen here ?
There is more choice 

One thing I learned the hard way, is that the derailleur cable on a road/gravel bike exit at the very end of the chainstay/seatstay, after the axle.
While on an MTB, it exits from the right chainstay before the axle.
If you want to put a cable actuated Eagle derailleur for instance, you'll need some 3D printing or other hackerish solution.

I couldn't remember who recommended this one but I tried it and WOW, was it painful.

My bet, it's me  ... sorry.
I buy it. If you don't do anything with it, and can send it to a friend in Phoenix AZ(from Austin right?).
PM me.

Thank you for this post! You have built basically the exact spec that I am planning to build. The only difference I'm considering at this moment is to use the FM 909 frame. But if I go with the FM 936, my bike will be identical to yours except for color, blipbox, saddle. Maybe tires too of course. I was very hopeful to stay well under 10.5 kg, and you've just shown me that this can be done. And even with some nice goodies like AXS and a power meter.

I am coming from a hard tail that I have been riding for 7 years now. So moving to a full suspension with modern geometry is going to be mind-blowing.

What ?!? You don't like my saddle ? It is very comfy you know
Coming from the same hardtail years as me. Mind-blown you'll be for sure !

Ho trovato questo nuovo telaio con angolo forcella 68,5 di workswelles.
https://www.workswellbikes.com/XC/wcb-m-336(29er).html
https://www.facebook.com/photo/?fbid=849033382315401&set=pcb.849033748982031&__cft__[0]=AZXfClPyVGS3ZvsUxWAP1FwCSsuX1azgqSXmDRM2oK2k4BOa1A46-2lXLMGeo_5p5YaUwXTY2W9IK269OS0ta7Iicp4fSQ5A4SjfAWfO8rXjwKWBxbhByHBN1eECLarJnkI&__tn__=*bH-R

Nice find, thank you !

Here is my bling build !

The weather isn't very nice here, so only two ~70km rides so far.
But I loved every instant of them, a smile from one ear to the other, even once when I crashed it

Not sure if it is the geometry, the full suspension, the seatpost or the electronic shifting in particular, but this has little in common with my past hardtail riding.

It is a size M SL.
OG-Evkin bar
Ligthbicyle XC925 wheelset with DT-Swiss EXP 240.
XX1 AXS derailleur + Blipbox + Multiclics
SID Ultimate 120mm and SIDLuxe shock 42.5mm
Piccola brakes
Reverb AXS
2.35 tires.
And 10,1kg

The commands are, left click easier gear, right click harder gear.
Click on both for the seatpost.

I was hoping for a more greenish blue, than this reddish one, but I start to get used to it 

I'm still testing different 3D printed mounts for the blips for different positions.
For now the cables are taped below the bar, my plan was to make them go through the bar end and exit through one of the mount holes.
But there was some sun, and I preferred to go ride than work more on it. Maybe later.