Connecting Ring Alarm Pro Base Station to a router provided by internet provider

I am having severe performance issues with my Ring Alarm Pro Base Station / Eero Pro 6 mesh network. Other participants can't understand me on simple WebEx video conferences and WebEx regularly reports network issues on my side. Streaming video from Hulu, Disney+, etc. regularly pauses for buffering, even Spotify pauses for buffering! It is the issue for both my wifi and my ETH connected devices (connected to a switch on the Base Station's spare ETH port). I have had Eero techs try to troubleshoot it and they say it's not the eero. I have also had the Spectrum cable tech in to troubleshoot the broadband and he says it's not in their portion of the network. I believe it's the Base Station that cannot handle HD video. I want to install a router from Spectrum to handle routing/gateway/local ethernet connectivity and use the Alarm Pro/eero pro 6 for the Wifi mesh in the house. This will also prove which device is at fault if my hardwired devices to the Spectrum router no longer have bandwidth issues. How can this type of a setup be configured?