Can the Apple Watch Ultra 2 use GPS only?

No, you do not have to use the cellular function and the Ultra2 will do everything through the paired iPhone.

However, if you want an Ultra 2, you need to buy it in the next couple of days from Apple. Due to a legal challenge over a patent for the Blood Oxygen sensor, Apple is pausing selling the Series 9 and Ultra 2 watches online on the 21st and in their retail store at 3 PM ET on 24 DEC.

M1 Mac mini, macOS 14.2;  Watch, series 7 GPS/cellular, watchOS 10.2; iPad Pro 2nd Gen, iPadOS 16.7.3; iPhone 12 Pro, iOS 17.2; TV 4th Gen, tvOS 17.2; HomePods, audioOS 17.2 and Airport Express w/ Airplay 2

Only the Series 9 and Ultra 2 have been listed for a pause in selling for now. Those are the two devices in the ITC import ban.

It is said that Apple is working on a watchOS update to remove the patent offending Blood Oxygen function.

Oldskoolmark wrote:

Another question is will Apple still be selling the Ultra version 1 in store or is this included

in the selling issue ?

Apple stopped selling the original Ultra in September.