Having to restart modem multiple times a day

Xfinity had an outage in my area 8 days ago. Ever since then, I’ve had to restart my modem/router at least 2-3 times a day as it seems to hang up/stall after a few hours. It’s now to the point it is happening after about 15-30 minutes. I’ve switched out to a brand new router/modem (that is on xfinity’s preferred list) and it still does the same thing. The router is up to date. I’ve tried factory resetting and reinstalling all of them without any improvement. Internet is now crawling it’s so slow. I don’t know what to do.