PowerShell modules are an easy way to automate. There are modules for many technologies such as VmWare, Azure, AWS, SecretServer, SQL etc; a module for FME Flow / FME Flow Hosted API v4 is missing. Possibly Autorest can be used to archive this: GitHub - Azure/autorest.powershell: AutoRest PowerShell Generator - it would be greate with integrated help-files, standard names, much more.
$cred = Get-Credential
$repo = get-FMEFlowRepository -server fme.contoso.com -Credential $cred | where name -like "*myrep*"
Invoke-FMEFlowWorkflow -Server fme.contoso.com -Repository $repo -Workflow test.fmw -Credential $cred