You know that Giant is from Taiwan, that can be seen more Eastern than China 
My theory is, if you look at a top end branded bikes, you'll pay about half or less, the price for the same or better equipment.

Don't buy on the first shiny aliexpress seller you find, but do some homework by reading here what sellers have good reputation.
Personally I value more after sales service and reliability of a Chinese brand building their own models, than sellers of copies.

I'm having a hard time to find a frame for a 1.95m guy that is less flexible than you.
I would go for this one https://www.flybike-asia.com/product/148.html ( by Carbonda ) if I didn't have to put 6cm of spacers under his stem although Carbonda told me it is safe.
You should have more luck.

Do you have any opinion regarding the performance of your FM909 or FM936 compared to something like an epic evo frame perhaps?

My bike mate is a recidivist S-Works victim . He paid his Epic Evo twice as my bling FM936 that is lighter, has more travel and better components.
And I can't see any advantage with Brain on climbing compared to my always open setup.

My FM909 frame in size "M" weight 1874gr...

A super light size L from a recent order, is about 2kg with some removable plastic parts

"There is a rider weight limit of 90kg for these cassettes" is kind of strange limitation, how about watts ? 

Wondering what is the advantage of such wheels ? Stiffness ? Aero gains ? Not weight apparently 

I've ordered an XC wheelset for a build, from lightbicycle with their carbon spokes, on normal hubs.
I look forward to see how this looks, weight and ride.

Looks like Carbonda uses 7mm bearings...

I was just looking today about stainless steel bearings.
Found these that were 7mm too.
Hopefully to have them resist a bit longer to rust, the top one.
https://a.aliexpress.com/_EvdnnrJ

Anyone has experience with A-Ex gloves?...

I tried quite a few, each time the size was kind of odd even when following their size charts.
And the finish and quality were not good.

I purchased the Igsport iGS630 from Amazon back during their Amazon Prime Days.   I really love this version of the IGSport  bike computer.   

The iGS630 still isn't available on Aliexpress, only the iGS620.

Is it really many hours of autonomy?
This is my only gripe with the Karoo2.