The Apple Watch series two ultra won't have AI. I can say this with certainty because when a product with a radio is to be made available for sale in the US, it must be tested by a government agency called the FCC. All technical details regarding communication are publicly available here for the Apple Watch Series 2 ultra: FCC ID BCG-A2986 Apple Watch by Apple Inc.. As you can see, the lowest frequency it can communicate on is 13MHz (NFC). The next lowest is 699MHz, and so on - up to 60GHz.
Hoseless AI transmitters use the Low-Frequency band (30kHz-300kHz) because that's what will travel through water fairly well. There's no unlicensed use lower than LF. For example, the Shearwater swift transmitters use 38kHz. Unlicensed use means the person using the product doesn't have to purchase a license from the FCC.
Maybe some future Apple watches will have such a feature, but this one does not.
What if it used ultrasonic instead of RF? Like the Garmin does.