RX50 2.4g download speed very slow

Hi Furry and thanks for your reply.  See my answers below.  Before I respond, my ,speeds have nee percent until recently  Nothing changed on my end or from the ISP.  I also worked in Broadband for years as an engineer for a major company and am baffled by this issue.

What Firmware version is currently loaded?

Most recent for the RX50 and no new updates available as I checked

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

I use a Netgear COX (my ISP) certified CM1100 which is connected to my Netgear RX50

Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended. 

LAN cable if fine.

What connection rates are you seeing with devices connected on 2.4Ghz. 

Getting very good rates and even have some streaming using 2.4Ghz

Is Smart Connect enabled or disabled?

Smart connect is not enabled nor would I enable it as some of my devices cannot toggle to 5 from 2.4 and has been disabled since I have configured my set up for 3 years now

Do you have 40Mhz channel width set?

20/40 Coexistence is enabled

Most 2.4Ghz devices will cap out at anywhere from 50 to 100Mpbs depending on there design and support. 2.4Ghz mostly will never see speeds near 800Mpbs. " 2.4GHz AX: 2x2 (Tx/Rx) 1024/256-QAM
20/40MHz, up to 600Mbps" <This is a connection rate only between the router and wifi devices that support this connection rate. This differs from bandwidth speeds.

Fully agree about the Cap out rates, but previously I have gotten at least 300 Mbps.  I also know it is not the Modem as of course (stating the obvious) when I cam using ethernet the speeds are much higher for Download.  If you think of anything else please let me know.

Thanks:  Joel