Decommissioning Exchange 2013 Hybrid

Hi Folks, 

We have an Exchange 2013 Hybrid setup which consists of two servers (2013 Mailbox server and 2016 Hybrid Connectivity server). All mailboxes are migrated to 365 including the SMTP relay service and nearly nothing depends from the  on-premises Exchange now.  We're looking at safely decommissioning the Hybrid Exchange (Hybrid AD will remain as is) and fully operate from 365. 

What are the exact steps required here and are there any risks associated in this ? appreciate any thoughts, inputs.