Pairing replaced Watch series 7 with iPhone X

So I own an Apple iPhone X (6 years) and an Apple Watch Series 7. Due to a hardware failure (black screen), Apple Customer Care has decided to replace my Apple Watch with a brand new one (thanks Apple 😊).

The problem:

my previous Watch was on an earlier version of Watch iOS, because my iPhone X is not compatible with iOS 17 nor 18. As the new Apple Watch comes with the newest Watch iOS, I get an error message “Pairing failed - update iPhone to the newest iOS software”.

is there a workaround?

Your help is appreciated!