There has a known issue for ALM 15.0.1 installation on Windows Server 2019. R&D team already found out the solution and workaround to resolve it.
"Flexeraax2$aaa: Windows DLL failed to load".
We recommend setting the following environment variable for Java before installing ALM,
JAVA_TOOL_OPTIONS= "-Dos.name=Windows Server 2016"
If the variable already exists, append the value "-Dos.name=Windows Server 2016" to it.
Remove the value from the variable after the installation.