If you're on a business connection try swapping to using a Public IP, this seems to resolve the problem. I *think* the problem is CGNAT, currently most commercial routers don't seem to handle it well when the connection drops. Switching to Public IP eliminates this.
We had to switch to Public IP so we could use some port forwarding, when we made that change the connection remained stable despite the occasional lost signal.
Draytek 2766, WAN 2 set to Always ON rather than ARP or ping detect.
This won't work on a regular account as you can't currently get a Public IP.