Hi there,
Greetings!
I understand you need to customize your Dynamics 365 instance to pull Customer / Custom fields in to the Contact entity.
My portfolio has some samples of my work in Dynamics CRM - please do review and let me know if you need more info.
One of the projects I configured was a sync from a custom entity to Contact and vice-versa.
Would be great to understand your requirement in more detail.
Looking forward to connecting with you to discuss this.
Thanks,
Regards,
Rajesh Menon