pcie lanes throw thunderbolt ports

[AliNabeel]

Dear hp community,
With new technology being develope we see connecting graphics card throw thunderbolt ports.
I heard that a thunderbolt 3 port use 4 lanes of pcie gen 3 thats mean 4GB of data per second and a desktop graphic's card use 16 lanes that's mean 16GB of data per second but the graphics card dont use all the lanes that is connected to i also heard that the maximum bandwidth of graphics card data throw pcie is 8-6GB/s so that's mean losing 20-50% of maximum performance using thunderbolt 3 comparing to connecting the graphic card to a pcie slot and that's ok to play modern games with high settings.
The problem is some companies make thunderbolt 3 ports with only 2 lanes so 50% of maximum performance drop comparing to thunderbolt 3 4lanes the result is 40-75% of maximum performance drop comapring to pcie slot as a result,lots of frames drop playing games reaching a level that cant be played with good settings so:
1)Why companies dont mention that with the spec of the laptop as i didnt find any offical source to tell me how many pcie lanes in my laptop?
My device is hp sepctre x360 2-in-1 15t 2018 i7 8705g with amd vega rx m gl 4gb i have 2 thunderbolt 3
2)Are the ports using 8 lanes of pcie so i can use one thunderbolt port for external graphics card with about 25% of maximum performance drop and one port for usb hub as i have only one usb 3 and i want to connect a mouse,keyboard,web cam,...etc or they are 4lanes of pcie connecting in a way in which if i use one port i use four lanes and if i use the another port i get 2 lanes for each port or i have two pcie lanes in each port and cant be four lanes if i use only one port?
3)If i disable the amd graphic card will i get more lanes?
4)If i connect a device with the usb 3 that i have will i lose more lanes?
5)There is a model that have iris gpu and another model with intel uhd graphic card and another model with nvidia mx 150 so does disabling the igpu can let me use 4 lanes in each port as they also use pcie lanes?
3)I wish hp or other companies tell users more about their laptops so we can choose the right laptop so can i contact someone on hp to suggest that?

[Barachiel]

@AliNabeel

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