Do I need to exchange my XB6 to XB8 modem?

Hi I just upgraded my router to Eero Pro 6E and it supports wifi 6E now. I am wondering if XB6 is still compatible with my new eero routers or should I upgrade to XB8? I also found that my internet speed will randomly cut off(very low 1~5 mbps) at night around 8 to 12pm.