I will take a stab at this. Depends on how you were notified and is it really end of life or defective, which you did not say. Most cable companies have lists available, on line, about what modems are still supported.
I know Comcast had a mix up about a modem months ago.

"Sometimes" s best to speak with support. DSLreports usually has good information about this stuff. That is my first stop in a similar situation..

Yup, cant agree more. What kind of modem will work with your service, what requirement for the modem, that's something the cable company should tell you

I have a modem that works. I purchased the TP-Link router because the Asus one I got had a flaw and returned it. I do not understand the value that has to be
entered in the TP-Link. I never had an ISP that used IPV6 before.
The IPV6 settings for OpenDNS
2620:ccc::2 and 2620:ccd::2 but that value seems to be different.

Ohhh yeah, TP-link's modems are the best)

JonesACraig wrote

Ohhh yeah, TP-link's modems are the best)

can't agree more