Thunderbolt 3-to-Thunderbolt 2 Adapter Use

I have two 27" iMac desktop computers. One is a 2020 (purchased a month ago). It uses Thunderbolt 3.

I also own a mid-2011 27" iMac that uses Thunderbolt 2. Can I use the Thunderbolt 3 to 2 adapter to extend my 2020 IMac display to the mid-2011 iMac?

Do I need anything extra besides the adapter and a T/bolt 2 cable? I read something about an external power source(?). Does that apply to my set up description? I'm happy to provide more info if required.

The T/bolt 3-to-2 lash up seems to be the simplest, most elegant solution. Are there any other (less expensive) options out there?

Thank you...I look forward to your responses.