A cloud-based service included in Microsoft 365, delivering scalable messaging and collaboration features with simplified management and automatic updates.
It's not the same, for one using Dynamic Office 365 Groups requires Azure AD P1 licenses. Dynamic DGs are Exchange-only objects, thus you can only use Exchange-related objects and attributes when configuring membership. Dynamic O365 Groups are authored in Azure AD and can be used by any service that supports groups. They come with all the "standard" O365 group stuff - mailbox, ODFB site, etc. But are also limited in the types of recipient/rules you can create.