I'm not completely sure about this, as I don't have a cable connection to my house (only fiber) so I never paid attention. But AFIAK the major cable providers here allow you to configure the supplied modem-router into passthrough mode (thus, only acting as a modem) so you can install your own router behind it.
I have never met someone who attempted to install their own cable modem. I do know that the cable modulation standard (DOCSIS) is wildly complicated, so even buying the right type of cable modem for your connection would be challenging. There may also be licensing issues involved that would prevent you from buying such modem completely.
I know some cable ISPs outside NL will allow it if your modem is from a reputable brand without any known issues (and compatible with whatever DOCSIS version they're using of course). Ziggo's "connectbox" modem/router even in bridge mode has quite poor latency stability so I was hoping I could use this law to persuade them to activate an Arris SURFboard or some other decent brand modem.
I have never met someone who attempted to install their own cable modem. I do know that the cable modulation standard (DOCSIS) is wildly complicated, so even buying the right type of cable modem for your connection would be challenging. There may also be licensing issues involved that would prevent you from buying such modem completely.