Apple Watch ultra 2 screen protector

AFAIK, Apple doesn't recommend one but also don't discourage using one.

I've always used Spigen screen protectors on my iPhones and my  Watches. They come with an application jig that makes installing them correctly foolproof!

https://www.amazon.com/Spigen-Tempered-Screen-Protector-designed/dp/B0BCXFZVH8/ref=sr_1_19?crid=2UKPU19QMTMRF&keywords=Apple%2Bwatch%2Bscreen%2Bprotector&qid=1696741759&sprefix=apple%2Bwatch%2Bscreen%2Bprotector%2Caps%2C127&sr=8-19&th=1

M1 Mac mini, macOS 13.5.2;  Watch, series 7 GPS/cellular, watchOS 10.0.1; iPad Pro 2nd Gen, iPadOS 17.0.1; iPhone 12 Pro, iOS 17.0.1; TV 4th Gen, tvOS 17; HomePods, audioOS 17 and Airport Express w/ Airplay 2