Yes, December 2019 (KB4484195) is the latest update for SharePoint server 2010. You don't need to install all the updates.
To apply December 10, 2019, cumulative update for SharePoint Server 2010 (KB4484195), you must have Microsoft SharePoint Server 2010 Service Pack 2 (SP2) installed.
Installing SharePoint 2010 Cumulative Updates for your reference:
I am working on assignment to update Sharepoint 2010 Farm Servers ( app and WFE servers) Patch update from SP1 to latest one, can you please guide what should be the steps.
Please correct me if I am wrong; that CU will include all the old patches update including SP2 ?
Do I need to install Dec 2019 Updates ( is it the last and latest CU update available) ...