Target display mode with iMac 2017 and MacBook Pro 2017

Good morning,

I need some help…

I would like to use my iMac 2017 as the main monitor and my MacBook Pro 2017 as an extended monitor. I bought a thunderbolt 3 cable but it doesn’t work. The MacBook Pro remains on the main monitor and I can’t change the setting. If I try the opposite (MacBook Pro as main monitor and iMac as extended) I have the same issue, I can’t change the setting of the iMac from main to extended monitor. 

I have read some article on the web and found out that the Macs after 2014 don’t support the target display mode anymore. Is it correct? Does this mean that I can’t connect those two Macs in any way? 

I have also called the support and chatted a couple of times but nobody is been able to resolve the issue and give me a solution.

I don't know if I am asking the impossible but I would just like to know if I can use one of my Macs as the main monitor and the other one as an extended monitor in some way. Is it possible? 

Please see below the specs of my Macs.

iMac:

21.5-inch, 2017

Mac OS: Ventura 13.1

MacBook Pro:

15-inch, 2017

Mac OS: Ventura 13.1

Thank you 

Marianna