Macbook Pro 16 M1 Pro 2021 does not find iPad Pro 12.9 2021 as a display (sidecar)

Have you verified that you meat all the requirements?

Sidecar system requirements

Sidecar requires a compatible Mac using macOS Catalina or later and a compatible iPad using iPadOS 13 or later.

• MacBook Pro introduced in 2016 or later
• MacBook introduced in 2016 or later
• MacBook Air introduced in 2018 or later
• iMac introduced in 2017 or later, or iMac (Retina 5K, 27-inch, Late 2015)
• iMac Pro
• Mac mini introduced in 2018 or later
• Mac Pro introduced in 2019
• Mac Studio 
•   
• iPad Pro (all models)
• iPad (6th generation) or later
• iPad mini (5th generation) or later
• iPad Air (3rd generation) or later

Additional requirements

• Both devices must be signed in with the same Apple ID using two-factor authentication. Sidecar does not support Managed Apple IDs.
• To use Sidecar wirelessly, both devices must be within 10 meters (30 feet) of each other and have Bluetooth, Wi-Fi, and Handoff turned on. Your iPad must not be sharing its cellular connection and your Mac must not be sharing its internet connection.
• To use Sidecar over USB, your iPad must be set to trust your Mac.

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