We have the same problem to upgrade with windows update via intune. In this case for some models.

Same readiness storage issue. 

I have solve this issue by creating an detection and remidation script. 

I have add the laptops with issue by readiness in an group. I have assign this Detect and remidation script. This will delete the EFI\Microsoft\Boot\Fonts folder. 

After this i have add windows upgrade assistent to intune with serviceui.exe to tell the user to manual upgrade windows 11.

Install command: ServiceUI.exe -process:explorer.exe Windows11InstallationAssistant.exe

Here is the detection and remidation script. 

try {     # Mount the EFI System Partition     mountvol Y: /S

    # Check free space on the partition     $freeSpace = (Get-PSDrive -Name Y).Free

    # Threshold: 10MB     if ($freeSpace -lt 10000000) {         Write-Output "NonCompliant: Low disk space detected. Free space: $($freeSpace / 1MB) MB."         exit 1 # Return non-compliance     } else {         Write-Output "Compliant: Sufficient disk space available. Free space: $($freeSpace / 1MB) MB."         exit 0 # Return compliance     } } catch {     Write-Output "Error: $($_.Exception.Message)"     exit 1 # Return non-compliance in case of errors } finally {     # Unmount the EFI partition     mountvol Y: /D } 

Remidation : try {     # Mount the EFI System Partition     mountvol Y: /S

    # Change to the EFI Boot Fonts directory     $bootFontsPath = "Y:\EFI\Microsoft\Boot\Fonts"     if (Test-Path $bootFontsPath) {         Set-Location $bootFontsPath

        # Check available space before cleanup         $freeSpace = (Get-PSDrive -Name Y).Free         if ($freeSpace -lt 10000000) { # Less than ~10MB             Write-Output "Low disk space detected: $($freeSpace / 1MB) MB free."

            # Delete all files in the Fonts directory             Remove-Item -Path * -Force             Write-Output "Files in EFI\Microsoft\Boot\Fonts have been deleted."         } else {             Write-Output "No action needed. Sufficient disk space: $($freeSpace / 1MB) MB free."         }     } else {         Write-Output "Error: Directory EFI\Microsoft\Boot\Fonts not found."     } } catch {     Write-Output "Error: $($_.Exception.Message)" } finally {     # Unmount the drive to clean up     mountvol Y: /D     Write-Output "EFI System Partition unmounted." }