Good afternoon and thank you for your question. According to this article, use of Rest APIs have been deprecated. https://video2.skills-academy.com/en-us/graph/hybrid-rest-support
And also from this blog post of Exchange Team, it states that:
What API(s) should I use to work with Hybrid Orgs, where some mailboxes are in Exchange Online, and some are on Exchange Server?
You should continue to use Graph to work with Exchange Online mailboxes, and use Exchange Web Services (EWS) to work with Exchange Server (on-premises) mailboxes.
If you're using Exchange Server (on-premises), you should use EWS.
I hope I was able to answer your question. If it is, please upvote and accept it as an answer.
Thank you have and have a great day!