Need help. Just upgraded to a X55 Deco with an AT&T BGW320-505. setup went well but my download speeds are under 100 mbps. any specific setup help is appreciated.

Need help. Just upgraded from Deco M5 to an X55 with AT&T Fiber. All went well except my download speeds are under 100 Mbps and I have a 500 Mbps plan. Speed from AT&T to modem are 600+ but download s