I did order two M29 from Haideli, 69ºHA and 425mm chainstay in size M.
With a more reasonable and usual price for a HT: $350, then with accessories, paint and shipping to Europe at about $1400 for both.

Ehrm.. Katie sent me some pictures and a short video sequence and I said  "yes! Exactly like this". Yours is very different?

From the pictures, your blue looks more greenish, while mine is more reddish.

...My frame is also painted.  ...

It looks like the blue I wanted for my 936, what reference did you give them ?
Both frames, yours and azuzu501's look amazing !

I would look at something like https://www.espruino.com/ because it is a very easy way to learn and put some electronic intelligence.
I'm a coder, and your apparently simple need smells like the start of a very long, but interesting, journey 
Note, it is BLE not ANT+

The most common size bearing for Dub or 30mm spindle in a PF41 (a.k.a. PF86/PF92) shell in a quick web search is 30mm (ID) x 40mm (OD) x 7mm (W) - and there's no way you can fit two rows of balls in that, unless they're under 3mm diameter!

BBinfinite offers bearings in this size: https://www.bbinfinite.com/products/bearings-abec-7?variant=19203150381115

Wheels Mfg. has a genuine dual-row bearing BB kit for Dub cranks in a PF41 shell. They're custom bearings made by Enduro. The bearing OD is in direct contact with the BB shell: https://wheelsmfg.com/bb86-to-29mm-dub-flanged-dual-row-pressfit-86-92-abec-3-bottom-bracket.html

Cane Creek has a similar product in their Hellbender 70 line.

Not so cheap options unfortunately 

They don't have a published standover sadly!

Just ask Carbonda. They don't bite 

...Hoping the build quality and spike tension is good...

No worries. They are good.
I stopped building wheels since I order their wheelsets.

At the beginning, I was leveling the tensions of the spokes, to have them all equal by ear(getting them a very little out of true usually)
But I even stopped that.

I have a 062, the version prior to 162.
A Specialized inspired frame from 2016, and it was $439 all included shipped to Europe.
What an inflation...

This frame saw much more than it was designed for.
I did lend it to a friend that destroys everything, but not this frame.
So if there is no problem, I'm sure they do good frames.

Few years ago, I ordered them as well two 27.5" for kids and no problem either.

There are some posts here mentioning a rather poor after sale service.
And a crack or two.
But as usual when someone complains, you only have one side of the story.