@jhanes152
Some Ziggo modems seem to react allergic to VPN traffic, even in bridge mode. That has nothing to do with chipsets as such, but with the poor firmware in the Ziggo modem.
If you have a internet connection over coax, you always have a DOCSIS modem. It can be in the Ziggo modem/router, if it is in bridge mode or not, or in a modem/router that you bought yourself. The router functionality is separate from the modem functionality.
The important thing however for the way the modem behaves, is the question how well the DOCSIS modem firmware is maintained. You can be assured that it will be much better maintained with a modem/router that you buy yourself. ISP's hate modem/router maintenance, it costs money and effort.