rax70 internet speed decreases overnight until reboot

[philc11]

Im using firmware V1.0.1.78 and this is the "latest" today 23Nov20.  At reboot, internet upload and download speeds are great ~ 300MBps or more...after a few hours or overnight, we see a drop to 15-20MBps until reboot (then its back to normal).  How do I read the logs to figure out the problem or where else should I start?  I was on hold for hours last week and the "next level" or level 2 tech was supposed to call back (they did not).  This week, I called back as did my wife for hours and we just kept getting a new level 1 tech person who could not think past the prescribed script diagnostics.  Can anybody help before I pull out my hair and take this back to best buy?? lol....seriously, any suggestions?

[plemans]

what modem is it connected to? 

When the speed is dropping, are you connected to 2.4ghz or 5ghz? 

does wired speeds drop as well or just wireless?

[philc11]

Cable modem model cm1200 connected to the AX6600 (RAX70) wireless router .  Wireless speed on both 2.4 and 5 are slow after a period and I cannot directly connect to either the model or router (plugging in an ethernet cable does not work once the speed decreases).

[plemans]

Are you using wan port aggregation between the RAX and the CM1200?

[philc11]

I am not sure....the Ethernet Port Aggregation is Enabled (LACP-IEEE 802.3ad) (Port 1 & 2) but the status is "Ethernet Port Aggregation Status: Inactive" .  All of this is from the CM1200 http://192.168.100.1 access.  The router http://192.168.1.1 controls show

WAN Preference

WAN aggregation (1 Gbps + 1 Gbps)

[plemans]

Disable wan port aggregation on both the router and the modem. 

The cm1200's port aggregation seemed like it always had issues. its only really a benefit if you have greater than gig service. 

Once disabled, reboot the modem and the router. Just have the 1 connection from cm1200 to the router. (port 1 on cm1200).

Don't plug anything else into the cm1200 .