Question USB -C 3.2 gen 2x2 20Gbps beeing slower than 1x2 10Gbps.. why?

[Under Gamer]

Hello everyone,

I decided to run a speed test with my USB-C Samsung Portable SSD T5 on the two different USB-C ports of my Asus ROG STRIX Z790-E GAMING WIFI motherboard. One of them is a 3.2 gen 2x1 (10Gbps) model and the other is 2x2 (20Gbps). To my surprise, the SSD was faster on the 2x1 10Gbps model. I thought it could be because I was using the USB ports next to it and taking up bandwidth, but to my surprise, they are free.

I know it will be imperceptible in everyday use, it's just a matter of understanding why it doesn't make sense technically! Can anyone tell me what could cause this?

Thanks!

https://drive.google.com/file/d/1kTGLoTpneWLkACWUxITqwEaC7XqPIgbM/view?usp=share_link

 

[Under Gamer]

Another question, it's a 20Gbps USB input, wouldn't it be better for me to buy an M.2 NVMe Gen4 SSD and use it in an enclosure? Like this:

Porta USB	Velocidade do Samsung T5	Velocidade do SSD M.2 NVMe
USB 3.1 Gen 2 Type-C	Até 540MB/s	Até 5000MB/s
USB 3.1 Gen 2 Type-A	Até 540MB/s	Até 5000MB/s
USB 3.1 Gen 1 Type-C	Até 540MB/s	Até 1000MB/s
USB 3.1 Gen 1 Type-A	Até 540MB/s	Até 1000MB/s
USB 2.0 Type-A	Até 480MB/s	Até 480MB/s