Here’s the product page for the discontinued Uno WiFi:
That was an arduino.org product that used the same ATmega328P as the regular Uno and an ESP8266 for the WiFi. The Uno WiFi Rev2 uses the ATmega4809 and the ESP32. Both are significant upgrades spec-wise.
I don’t think you’re missing too much by not being able to get the original Uno WiFi. Since it was an arduino.org product it didn’t seem to ever get very good support and arduino.cc discontinued it once they took back over the arduino.org products.
I see the Uno WiFi product page does mention OTA, but the official Uno WiFi Rev2 product page does not. I wonder if those shops reused their product description from the Uno WiFi?
I would definitely contact the shop you bought the board from and ask them to correct their description. I’m sure OTA is coming, but they shouldn’t advertise it until it’s in place and working well.