recently we increased Internet speed up to 200 Mbps. through 5GHz Radio and LAN, I can get the 180 up/down the speed. but on 2.4GHz, still, it's 98 Up/Down.
does anyone have suggestions?
Your configuration looks fine, not sure if you are using channel bonding on 2.4 GHz, still, if you use bonding you will have an issue with your plan channels. I think this is a physical limitation on the 2.4 GHz band.
In general, Disable low data rate, use 20 MHz width, if you're using PSK then use WPA2 with AES-CCMP.