Watch SE

FYI, even with a GPS+Cellular watch you cannot get rid of he iPhone completely. You MUST have an eligible cellular service plan with a supported carrier. Your iPhone and Apple Watch must use the same carrier, and you must be within your carrier's network when you set up cellular on your watch. For more info, see:

Set up cellular on Apple Watch - Apple Support

With that said, you can buy a GPS+Cellular watch and setup the cellular feature later (or never).

There are 2 Apple Watch cellular radios

• Canada, U.S. Mexico, Puerto Rico

• The rest of the world

Carriers will not attempt to connect to an Apple Watch that does not use the correct radio.

If you do not get your Apple Watch in your own country, you may have to return the Apple Watch to the country where purchased to get warranty service.

If you do not get your Apple Watch in your own country, there may be country specific restrictions in the installed Apple Watch software that prevent features from working when you get home.

https://www.apple.com/watchos/feature-availability

So if you buy a cellular Apple Watch in Sloakia, or anywhere outside of the above listed countries, the cellular will not work in the U.S.

And yes, you can use a cellular Apple Watch as if it was a GPS only, and laster activate the cellular (assuming the cellular radio is compatible with the country/carrier you wish to use).