This. I’ve had similar problems with Comcast and I barked all the way to corporate until an entire army of techs and supervisors and the district VP was at my house fixing it. In the end I got new cables, new modem, new splitters and a dedicated signal test to make sure it stays up.
I still do what you do, I ping it every few minutes and if it’s down then I have a complex reboot cycle on the modem that has worked every single time.