Let me clue you in if you have any delusions about this: Yes, the polar bears will go extinct and not just this particular sub-group. Also, The Paris Agreement Goals are missed. This is a certainty.
If Paris Agreement Goals Are Missed, These Polar Bears Could Go Extinct - The New York Times
Polar bears in the Southern Hudson Bay could go extinct as early as the 2030s because the sea ice that helps them hunt for food is thinning, a new study suggests.
“We’ve known that the loss of Arctic sea ice would spell disaster for polar bears, so this might be the first subpopulation that disappears.”