Maybe different around the world and among ISPs. But I have always put any DSL modem I had in bridge mode and use my own router that I can do whatever I want with.
Sometimes it was possible to configure myself and sometimes I needed to call support and ask them to put modem in bridge mode.
But maybe different in different countries, but I don’t know of any problem why a ISP wouldn’t offer bridge mode.
Thank you raptor. I agree! In my case I was able to solve my issue with changing for dynamic IP number to computer name so did not need to add a separate router.