Is SDL Web-Build 22.214.171.124 compatible with Windows Server 2019? I am upgrading the OS to Windows Server 2019 in which I have SDL 8.1.
According to the documentation, only Windows Server 2012 R2 and 2008 R2 SP1 are supported.
Windows 2008 support ended a few years ago, and Windows Server 2012 will reach end of life later this year... so, I think the answer to your question is "No".
To upgrade the OS you will need to upgrade Tridion as well. While it may work with Windows 2019, there are zero guarantees that this is the case, and RWS support will be unable to help you as this is not a supported version.