Hello @Yordan Yordanov !
So it is Co managed !
Pay attention here please :
For Available assignment , it is only for user group. And for REQUIRED and UNINSTALL assignment, it can be applied to either user group or device group. Here is a link with more details for the reference.
https://learn.microsoft.com/en-us/mem/intune/apps/apps-deploy#assign-an-app
Also you have to transition the Workloads for Apps From Intune to appear in the Portal:
https://learn.microsoft.com/en-us/mem/configmgr/comanage/workloads#client-apps
There is a similar thread :
I hope this helps!
Kindly mark the answer as Accepted and Upvote in case it helped!
Regards