Hi Sk-73,
You could have conflict if you configure different settings in the profiles. The security baseline will be updated by Microsoft multiple times a year (frequently after a release) and if you want to change a setting you have to migrate to the newest baseline.
The purpose of the antivirus policy is not to configure a 3th party antivirus solution , but it's meant to configure Microsoft Defender.
It's up to you which profile you want to use, but if you configure both you have to configure the same settings.
I always use the Antivirus profile and set all the antivirus settings in the security baseline to not configured or the same as I have configured in the antivirus profile.
I've decided to use the antivirus profile instead of the security baseline or other profiles, because with the Antivirus profile you have more option to configure as what is included in security baseline. I want also to have the management of the configuration as easy as possible. So 1 place(profile) for the Windows Defender antivirus configuration
I hope this answer your question, please let me know if you have more questions.
If my answer answers your question, please mark it as the answer
Kind regards,
Rene