I used to have terrible DoS attacks.. so I do know what it is like.
The issue was on Cable. The company took a mind over matter approach.. we don't mind and you don't matter.
I moved to ADSL and it basically stopped. The problem with cable is the shared nature of the run.. and every infected computer on your run hammering every other computer. It happens also in building ethernet connections even worse.
To overcome it I ran a linux server/router with ACID and SNORT.
Domestic routers do not have the processor power to handle heavy attacks. (Unless you are in the >$200 range). But they also lack the firmware quality.
If you keep having issues once you turn on the protection (TP-Link btw are not great at this). Move to a linux or BSD based router .. eg PFsense. Or spend the money for an enterprise class firewall router.
The Apple router is not good enough and has no SPI firewall at all.
The Netgear router is domestic grade although the models >R7000 have loads of processor power the firmware is clunky. It is hardly ever updated. I would move to a third party.. shibby tomato for example.
But if you really have a terrible situation.. nothing beats an old PC with linux and real firewall.