I would first just try moving it around. Sounds like you have a wifi AC(5) router which is still very capable. But a lot of things can interfere with that signal. If you have a long enough cable move it into another room just for testing to see if your speeds improve. If they do then you know its the location.

usually on those routers b/g/n 2.4G speed is lowered when both 2.4G+5G turned on

So what’s the router and 2.4GHz device you’re looking at? Hitting 100 real world without going to 5/6GHz bands often isn’t gonna be easy

Even though it’s theoretically possible to get over 100mbps with 2.4 GHz, it’s mostly not the case in real world applications. I’d suggest just using the 5 GHz connection if you have a connection over 50mpbs.

Always good to look into

1.) What exact Make & Model is your Router and how old is it ?

2.) Do these “slow speeds” happen on only 1 device or all devices ?

“the only thing I want is my internet plan speed in 2.4Ghz band.”

That’s not really how any of this works. “internet speed” and “Wi-Fi speed(s)”… are 2 entirely different things (and not directly related).

Your day to day speeds are going to fluctuate,… because they’re affected by a wide range of things.

• Your ISP can only control the network-hops that it has direct control over. So for example if you are downloading something that’s 10 x network hops away,. and your ISP only controls the first 3 network hops outside your house,. there could be a potential slow down 5 x network hops away. .and that’s not your ISP’s fault and they can do nothing about it.

• Regarding Wi-Fi… speeds there are going to depend on a wide range of factors:… The device and OS,… the Wi-Fi chipset and Drivers,… and any environmental factors (distance, obstacles, reflection, etc)