Mirroring to MacBook Pro (Retina, 15-inch, Mid 2015)

Sidecar only goes Macbook to Ipad

Sidecar info - Use your iPad as a second display for your Mac with Sidecar – Apple Support

Sidecar system requirements

Sidecar requires a compatible Mac using macOS Catalina and a compatible iPad using iPadOS 13:

Mac using macOS Catalina

• 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, plus iMac (Retina 5K, 27-inch, Late 2015)
• iMac Pro
• Mac mini introduced in 2018 or later
• Mac Pro introduced in 2019
•   

iPad using iPadOS 13

• iPad Pro: all models
• iPad (6th generation) or later
• iPad mini (5th generation)
• iPad Air (3rd generation)

You can't.

You can use sidecar, but that goes Macbook to iPad, not iPad to macbook

Nope, but sidecar doesn't do what you wanted to anyway in your original post