sorting an array to find the longest folder path

PS Community,

I am doing an audit on a project to get the length of the folder structure, so as to ensure it can be exported out,

This is how I am populating the folder structure

$RootFolder = Show-PWFolderBrowserDialog

$Docs2Export = Get-PWDocumentsBySearch -FolderPath $RootFolder.FullPath -GetVersionsToo -PopulatePath

I want to sort Ascending to get the longest folder, but there is no option, even if I use -Descending it isn't sorting it right either

$Docs2Export.FullPath | Sort-Object -Descending { $_.FullPath.Length} | Select -Firt 1

What am I doing wrong,

TIA

Stephen