I want to unpair my Apple Watch from iPhone 11

my iphone 11 suddenly freaked out/jumped around, wouldn't allow me to access most apps. So, I got an iphone 16e.

Cannot access iWatch on old phone, so cannot pair it on 16e.

don't want to delete all iphone 11 but if that's the only way to unapair/pair I will have to.

Help.

[Re-Titled by Moderator]