Configure SharePoint Document Set

param (
    [Parameter(Mandatory = $true)]
    [string] $siteUrl,
    [Parameter(Mandatory = $true)]
    [string] $docsetCTName,
    [Parameter(Mandatory = $true)]
    [string] $columnsToAddToDocSet = "Company,Department",
    [Parameter(Mandatory = $false)]
    [string] $docSetToAdd = "CompanyA,CompanyB",
    [Parameter(Mandatory = $false)]
    [boolean] $enableModernLayout
)

Connect-PnPOnline -Url $siteUrl

# Activate Document Set feature
Enable-PnPFeature -Identity "3bae86a2-776d-499d-9db8-fa4cdc7884f8" -Scope Site -ErrorAction SilentlyContinue

# Ensure parent content type is available
$parentContentType = $null
while($null -eq $parentContentType ) {
    $parentContentType = Get-PnPContentType -Identity "Document Set"
    Start-Sleep -Seconds 5
}

# Create custom Document Set content type
Add-PnPContentType -Name $docsetCTName -ParentContentType $parentContentType -Group "Doc Set Content Types" -ErrorAction SilentlyContinue | Out-Null

# Add columns to content type
$columnsToAddToDocSet.Split(",") | ForEach-Object {
    Add-PnPFieldToContentType -Field $_ -ContentType $docsetCTName | Out-Null
}

# Exclude system libraries
$ExcludedLists = @("Access Requests", "App Packages", ... ) # (truncated for brevity)

Get-PnPList | Where-Object { $_.BaseTemplate -eq 101 -and $_.Hidden -eq $False -and $_.Title -notin $ExcludedLists } | ForEach-Object {
    $list = Get-PnPList -Identity $_
    Set-PnPList -Identity $list -EnableContentTypes $True
    Add-PnPContentTypeToList -List $list -ContentType $docsetCTName | Out-Null
    Set-PnPDefaultContentTypeToList -List $list -ContentType $docsetCTName

    # Create document sets and set metadata
    $docSetToAdd.Split(",") | ForEach-Object {
        $docSetName = $_
        $docSet = Add-PnPDocumentSet -List $list -ContentType $docsetCTName -Name $docSetName
        $docSetItem = Get-PnPListItem -List $list -Query "<View><Query><Where><Eq><FieldRef Name='FileLeafRef'/><Value Type='Text'>$docSetName</Value></Eq></Where></Query></View>"
        Set-PnPListItem -List $list -Identity $docSetItem.Id -Values @{Company="Company A"; Department="Finance"; } | Out-Null
        Write-Host "Document set '$docSetName' created and metadata set."
    }

    # Add columns to default view
    $DefaultListView = Get-PnPView -List $list | Where-Object { $_.DefaultView -eq $True }
    $columnsToAddToDocSet.Split(",") | ForEach-Object {
        if ($DefaultListView.ViewFields -notcontains $_) {
            try {
                $DefaultListView.ViewFields.Add($_)
                $DefaultListView.Update()
                Invoke-PnPQuery
                Write-Host -f Green "$_ column added to the Default View in library $($list.Title)!"
            } catch {
                Write-Host -f Red "Error adding $_ column to the View! $($list.Title)"
            }
        }
    }

    if($enableModernLayout) {
        # Enable modern layout for the content type
        $ct = Get-PnPContentType -Identity $docsetCTName -List $list
        $ct.NewFormClientSideComponentId = $null
        $ct.Update($false)
        Invoke-PnPQuery
        Write-Host -f Green "Modern layout enabled for content type $docsetCTName in library $($list.Title)!"
    }
}