Not the case in the U.K., dal or fibre doesn’t matter, domestically you typically have a standard sfp or other converter from anywhere which presents it as Ethernet which you then run pppoe over.

Tr069 allows the isp to remotely configure their equipment which most people are happy with, but if you want to use your own then that’s fine, and obviously unless you enable it the isp won’t configure your router or any other equipment.

Starlink acts far more than a media converter.