Con .NET Framework 4.6 API y Angular 18, en el mismo sitio, a mi me funciono esto:

    <system.webServer>
       <security>
        <requestFiltering>
           <requestLimits maxAllowedContentLength="2147483648" />
           </requestFiltering>
     </security>
         <modules runAllManagedModulesForAllRequests="true" />
     <validation validateIntegratedModeConfiguration="false" />
     <handlers>
        <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
        <remove name="OPTIONSVerbHandler" />
        <remove name="TRACEVerbHandler" />
        <remove name="WebDAV" />
        <add name="ExtensionlessUrlHandler-Integrated-4.0" path="/api/*" verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
        <add name="httpPlatformHandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified" requireAccess="Script" />
         </handlers>
     <httpPlatform stdoutLogEnabled="true" stdoutLogFile="./node.log" startupTimeLimit="20" processPath="C:/Program Files/nodejs/node.exe" arguments="./server/server.mjs">
         <environmentVariables>
             <environmentVariable name="PORT" value="%HTTP_PLATFORM_PORT%" />
             <environmentVariable name="NODE_ENV" value="Production" />
         </environmentVariables>
     </httpPlatform>
  </system.webServer>
</configuration>