@Ahmed Sh,Thanks for posting in Q&A.
I have done some research about this issue, here are some suggestions you can refer.
1.Hybrid AADJ device will only be assigned a primary user when the user logs into the device for the first time.
2.Based on my searches, you can try the method mentioned in the following link to enroll your device into Intune, but it will remove 3rd party identity/configuration services.
https://learn.microsoft.com/en-us/mem/configmgr/comanage/tutorial-co-manage-clients
3.If you want to enroll the device into Intune, it is recommended that you use User credential in Group Policy, but this method will not work with the SCCM cloud attach
https://petri.com/how-to-automatically-hybrid-azure-ad-join-and-intune-enroll-pcs/
Non-official, just for reference.
Hope above information can be helpful.
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