Did you follow the instructions from the ArduinoOTA library's documentation?:
https://github.com/JAndrassy/ArduinoOTA#installation
You do need to make the adjustment described by the library developer @Juraj here:
By that, they mean change this line of the sketch:
#include <WiFiNINA.h>
(WiFiNINA is the Wi-Fi library for boards like the Nano 33 IoT and MKR WiFi 1010)
to this:
#include <WiFiS3.h>
(WiFiS3 is the Wi-Fi library for the UNO R4 WiFi)
If you provide a detailed description of exactly what you tried and the problems or doubts you encountered while doing that, the forum helpers might be able to provide assistance.
I don't think it is a fair assessment. Obviously if you want to use the Arduino Cloud service then you must use the Arduino Cloud service. But Arduino Cloud is an option, not a requirement. You are free to do a nearly infinite number of other very significant things with the UNO R4 WiFi board without any use of Arduino Cloud at all if you don't want to use the service. You can find many such projects that Arduino community members have shared on the Internet. You are really only limited by your imagination and perseverance to work through the challenges that are to be expected when undertaking any complex technical endeavor.
There is absolutely nothing about the UNO R4 WiFi board that locks you into using the Arduino Cloud service. The Arduino company has created a free open source boards platform that implements the full standardized standardized Arduino core API for this hardware, as well as compilation, uploading, and debugger support. You can use that platform with open source desktop tools such as Arduino IDE, Arduino CLI, or 3rd party alternatives such as PlatformIO. The firmware on the board's "bridge" module is open source, and can be easily modified or replaced entirely with a simple Arduino sketch. The hardware is also open source.