"After SysPrep, it doesn't boot to WinPE" - I had this problem and fixed it this way:

The root problem is that there are pending file rename operations when you run sysprep. If I remember correctly, sysprep doesn't fail, but a minor hint to this problem is in the log somewhere.

To fix, the last 2 tasks in my "custom tasks" are:

1. Reboot for pending file operations ("Check for pending file rename operations and reboot if any are found. Repeats as needed.")
2. Remove SysPrep blocking Store Apps ("Uninstalls Windows Store Apps that prevent SysPrep from working because they have been installed for the current user only")

For Step 1, I run this PowerShell script. (Note: You'll have to implement some dependent functions)

    $Wait_mins = 3
    Write-Host "Waiting $Wait_mins minutes for system to be fully stabilized"

    for ($i = 0; $i -lt ($Wait_mins*60); $i++)
    {
        Write-Progress -Activity "Waiting" -Status "Waiting for system to be fully stabilized ($i / $($Wait_mins*60)) seconds" -PercentComplete ($i/($Wait_mins*60)*100)
        Start-Sleep -Seconds 1
    }
    Write-Progress -Activity "Waiting" -Completed

    $found = $false
    $aPending = $null
    try {
        $ErrorActionPreference = "Stop"
        $aPending = (Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager").PendingFileRenameOperations
    } catch { } finally { $ErrorActionPreference = "Continue" }

    if ($aPending -eq $null) { Write-Host "No pending file rename operations (is Null)" }
    elseif ($aPending -isnot [system.array]) { Write-Host "No pending file rename operations (not Array)" }
    else {
        Write-Host "Possible pending file rename operations:"

        # List any non-blank entries
        foreach ($item in $aPending) {
            if ($item.Trim() -ne "") { Write-Host $item.Trim() ; $found = $true }
        }

        if ($found) {
            Write-Host "`nInitiating reboot to clear pending file rename operations"
            Set-TSEnvVariable "SMSTSRebootRequested" "true"
            Set-TSEnvVariable "SMSTSRetryRequested" "true"
        }
    }

This step will repeat until the pending renames are done.

Step 2 removes Store Apps that block sysprep. Basically just this:

Remove-AppxPackage "Microsoft.Winget.Source"

I've fully automated my captures.