Ipad Pro 12.9 M1 - Does it able to provide 120hz (1080p or 2k) refresh rate to External Monitor ?

As you have established, Apple's published specifications for the fifth (and sixth) generation iPad Pro 12.9" states the highest supported frame rate for external monitors at the maximum support 6K resolution - this being 60Hz.

While the iPad screen supports 120Hz frame rate at full screen resolution, the published specification does not provide a breakdown of supported frame rate for lower resolution monitors.

As such, you might be best advised to seek clarification from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively, you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

What you say is false, most USB-C to HDMI or DP adapters that have sufficient technology such as DP 1.2 or HDMI 2.0, can transmit 1080p at 120hz or 240hz but the problem is that Apple has its data transmission system blocked at 60hz, why with an Android phone can I stream 1080p at 240hz with a USB-C to DP cable with DP version 1.2

If connecting your iPad to an external monitor via HDMI, you will need to use a USB-C to HDMI Adapter. Most commercially available HDMI Adapters are limited to 60Hz refresh rate.

Available published information concerning supported video connection refresh rates can be found here:

Charge and connect with the USB-C port on your iPad - Apple Support

My comments above reflect Apple's specifications for iPad - and observation of mainstream HDMI Adapters marketed as compatible with iPad.

I have made no assertion whatsoever concerning capabilities and specifications of Android devices.

Did it work for you at 120hz?

Ohh ok you have a good point, but I don't understand why Apple limits the hardware, I really like Apple but those little details are what make me not want to use anything from Apple