Weird issue with 5GHz Wi-Fi channels on Tenda AC9

[TukangUsapEmenq]

In a nutshell, I've just got myself an used Tenda AC9 router as an upgrade to gigabit LAN for my local network and to Wi-Fi 5 speeds.

 

I turned off the 2.4GHz Wi-FI (as I already got a 2.4GHz Wi-Fi on another router (TP-Link TL-WR840N) running WISP mode repeater, this Tenda AC9 that I just got unfortunately got issues with WISP). I tuned around the manual settings of channels and using 80MHz channel (there's no any 5GHz around me at all, yay!)

 

Yet. I set it to Channel 149-161 (whichever is available), I got Speedtest as-per below. This speed is for both of my phone and my laptop. Nearly the same result.

 

 

 

And below here is when I'm using my 2.4GHz Wi-Fi on my laptop.

 

 

 

And yes, I tried to change it to channel 36-48, still on 80MHz bandwidth. It kinda solved the problem but... My laptop (Thinkpad 11e Yoga with Intel Dual Band Wireless-AC 7265 adapter) doesn't seem to detect it at all. My phone (Samsung Galaxy A34) does the job fine and the test is on the spoiler below.

 

Spoiler

 

Since I wanna use 5GHz on both device, welp, how can I at-least solve it on the router, or on my laptop? 

 

**** EDIT AND ADDITIONAL INFO ****

 

I tumbled around Device Manager and advanced settings on my adapter settings. Changed 'preferred band' to 5GHz, and seemingly it can detect it. And also I tested the speed, runs exactly as the A34 speed above.

Spoiler

Problem is, when I disconnected from it, it's gone, again. And what I did to let my laptop reconnect is to tumbling around Device Manager again, and it works again.

 

Welp... It's not fun for keep opening Device Manager everytime I wanna browse on my laptop.. So still need the help here.

 

Thanks in advance.