Will Apple Watch series 10 with Cellular purchased in US work in Israel?

If you buy an Apple Watch abroad, these devices are supposed to be used in the country of purchase, due to the different built in hardware, that has to support local carriers, especially if it comes to LTE.

So make sure that your carrier in Israel supports this model and all its features.

And the watchOS is also country specific. An Apple Watch bought in the USA will always install the watchOS version and all available features for the USA. Features that are specific to the watchOS in your country, will not be supported in that case.

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copied from: Apple Watch - Carriers - Apple

Also remember, that the warranty for an Apple Watch can be restricted by Apple to the country of purchase.

In case of a warranty claim, you will have to bring the watch back to the country of purchase, Apple Support does not ship internationally.

Legal - Apple Watch Warranty US - Apple

It will most likely work.

Model # will prevent O2 sensor for working due to import ban in the U.S.

No warranty.

And the watchOS is also country specific. An Apple Watch bought in the USA will always install the watchOS version and all available features for the USA.

This is not true.

An Watch will install the version of watchOS configured for the country in which the watch is being updated.

For example, if you buy an Watch in the US with a functioning ECG and then take the watch to a country where the local authority for medical devices has not approved the ECG function, that function will be deactivated the first time the watch is updated in that country. Many Watch owners have reported this over the years since ECG was introduced.

Then it should be easy to disable the shutter sound on iPhones, sold in Japan, just by updating the iOS firmware outside of Japan. Which, as expected, does not seem to work:

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copied from: iPhone 13 Japanese version - Apple Community

I’m not sure that is applicable to all situations or even Watch models. Camera shutter sounds are mandated by law that they always be on. This is well known limitation in the camera industry and many countries in Asia require the camera shutter sound. It wouldn’t surprise me if Apple just hardwires sounds on so a software update doesn’t accidentally enable camera sounds. It does illustrate that to comply with local laws and restriction Apple may do either hardware or software restrictions.