Unable to pair my Apple Watch SE to iPhone XR

I am trying to pair my iwatch SE to iphone XR. Each time I try to pair it says my version on ios needs to be updated to 18. I have automatic updates and my phone is updated to ios 18 as far as it can go. It does not even offer manual updates to do. I restarted my both devices but no change.

The iwatch is new and the phone is old if that is important.

[Re-Titled by Moderator]