Is it you’ve had issues before with a Broadcom based router?
Broadcom are ahead in the WiFi 6 for routers compared to Qualcomm but recently there’s been a snippet about trading but that’s something you would need to Google regarding Broadcom.
Im using an Arm based router but here’s the thing, it does not matter when it comes to chipsets unless you are looking in specs and standards but it’s down to the manufacturer to implement those features and all routers have bugs so firmware comes into play.
Dont forget there are other chipsets inside as well that some use for various processes from WiFi to switches.
with your ECI modem you can use any router that’s not a combi model, you just need to decide what your requirements for your network are and then narrow down the choice.