Need to use iMac 27" 2013 model as display for MacBook Pro 2021
The Apple store sold me a Thunderbolt cable MD862LL/A which works as both Thunderbolt and Thunderbolt 2 from what I understand. They also sold me the Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter MMEL2AM/A. The iMac 2013 isn't a Thunderbolt 2, it's just Thunderbolt. So it's not working and I'm pretty sure it's because the adapter needs to be able to read the older model Thunderbolt connection (not the Thunderbolt 2). Is there such an adapter available to make this work? Everywhere I've looked online says it's possible, but no one offers the way to make it work. I've made the cable/adapter connections, checked all the Display settings on both the iMac and the MacBookPro and there is no recognition between the two. HELP! and THANK YOU IN ADVANCE!
iMac 27″, macOS 10.15