RAX12000 WiFi Speed Slowdowns Daily

Hi All - In October 2019, I bought the CM1200 modem and the RAX120 router. The modem has been solid, but I have had speed slowdown issues since day 1 with the router, requiring a reboot every 12-24 hours to get the speed back up from 20 mbps to 800+ (I have gig internet).  I have tried a factory reset and reverting back to firmware .114 from .118. Neither fixed my speed slowdowns. 

Seeking any possible help from the community. I tried contacting Netgear via Twitter for help, but they pointed me to the support page and community - my support has lapsed, and I'm not going to throw more money at this problem on top of a router that never properly worked. I posted about my issue in another thread here (which some others had the slowdown issue as well), but the thread was dedicated to the RAX120 reset issue people experienced in March, so I'm hoping I may have more luck with a thread specifically for the slowdown issue. I also replied to their recent Reddit AMA asking for help with no reply.

Anyone have any idea what issues may cause this with this specific router, or potentially anything generally going on in the network that may be causing this?

As background (in case helpful) setup has:

• Netgear CM1200 modem which goes to the Netgear RAX120 router.
• 1 switch hooked up tot he router that has hardwired Smarthings hub, Lutron hub, and Desktop PC
• Wireless has 31 devices according to the app, ranging from laptops, iphones, sonos speakers, consoles, streaming boxes, lights, etc.

Thanks!