Unable to build project from PowerShell

From PowerShell the specified project in the solution I would like to build via VisualStudio.DTE.
It doesn't work
I probably need to go down the hierarchy of solution folders in the solution
I don't know how to do it

The solution consists of:
Solution Folder
│ -- Project 1 folder
│ │Yes -Project.csproj
│ <
│ -- Project 2 folder
│ --Projec2.csproj
<
--Solution.sln
--Build.ps1

Here's the code:

$VSDTE=New-Object-ComObject VisualStudio.DTE
$VSDTE.MainWindow.Visible=$True
$VSDTE.Solution.Open("$PSScriptRoot\○○○○.sln")
foreach ($prj in $VSDTE.Solution.Projects)
{
    // I want to get out of the hierarchy here.
    $VSDTE.Solution.SolutionBuild.BuildProject("Release", $prj.UniqueName, $true)
}

$VSDTE.Quit()
System.Runtime.Interopservices.Marshal :: ReleaseComObject($VSDTE)

Reference
MicroSoft Docs EnvDTE Namespace