Target Display Mode not working on MacBook Pro 13" 2020

Same issue here!

New 2020 MBP, using an apple USB-C to thunderbolt adapter, apple thunderbolt cable, mid 2011 iMac.

Apple support just informed me that they don't have this feature in newer devices. What a shame!

I'm filling out a feedback form suggesting that they bring it back. Perhaps naively hopeful that they'll respond but worth a shot.

I have the exact same problem. I spent about an hour with Apple's support team providing information. They are working on the problem, with one possibility being an issue in the latest Catalina update. I am running 10.15.4 on both my MacBook Pro (which is working) and on my wife's MBA (which isn't working). I updated the MBA to the latest Catalina version before trying Target Display Mode, so I don't know if it would have worked prior to the latest Catalina update.