Windows Server 2019 follows the Fixed Lifecycle Policy. The Fixed Lifecycle Policy applies to many commercial and some consumer products currently available through retail purchase and/or volume licensing. https://learn.microsoft.com/en-us/lifecycle/policies/fixed
We recommend upgrading to the latest version of Windows Server. Running the latest version of Windows Server allows you to use the latest features – including the latest security features – and delivers the best performance.
Overview of Windows Server upgrades https://learn.microsoft.com/en-us/windows-server/get-started/upgrade-overview
Hope this resolves your Query !!
--If the reply is helpful, please Upvote and Accept it as an answer–