https://forum.netgate.com/topic/173013/what-can-the-isp-see
os version via OS fingerprinting
https://superuser.com/questions/840412/what-information-can-my-isp-see-from-my-router
https://www.reddit.com/r/techsupport/comments/okqhzd/can_isp_see_what_3rd_party_router_im_using/
dont expect any support from isp is you’re using 3rd party routers
Options if router doesn’t allow changing DNS and DHCP settings
https://www.reddit.com/r/pihole/comments/1dqq95w/options_if_router_doesnt_allow_changing_dns_and/
- I’m not sure if this is relevant to the Router cant change DNS issue because the router I have is not ISP provided.