Network speeds not what expected

[Noishpa17]

Recently switched to 2 gbps fiber (Frontier) internet, so purchased GT-BE98 for wired ports and future proof speed availability.

Hooked up router to modem and set up using tablet/phone app. From the ASUS app I am able to speed test the router and it shows 2gbps u/d. However when connecting any device (sitting next to router) to either wired or any WiFi (2.4 or 5) I get 300-700 mbps d speeds. 

I have QOS off in settings, traffic analyzer off in settings, using separate 2.4,5,6 setup, WAN connection type Automatic IP. 
What else can I do to attempt to get the speeds I should be getting.

[jzchen]

EDIT-  My apologies you noted the router model already...

What Ethernet speed(s) do your wired devices support.  You should be getting (close to) 2 Gbps on most of the ports on the BE98....

[Noishpa17]

I'm getting 700-900 from wired through ethernet. Confirmed the cord and length can do higher as checked them from modem to router and using router speed test. So I'm really at a loss. 

[Saltgrass]

Have you tried going from the modem directly to the other device, such as a computer?  Is that what you mean by "wired through ethernet"?

Are you using the Frontier devices as they suggest?  

Do any of your networks have a VLAN configuration?