Match/move based on data in the title of a document to folder of the same name

Question

So I have a Library with a list of documents. These docments (PDFs) are named in the following format.

1. DeptCode_MgrNumber_MgrLast,MgrFirst_EmpName_634242

I would like to find a way to

1. Build a folder for each manager.
2. Break inheritance for each folder so only the manager can view the contents.
3. Merge the appropriate documents into the correct folder ( eg managers will have multiple files with their name on it.

I have a great script that builds the file structure (steps 1 and 2) and strips the permissions of each folder. As follows.

#Connect to this Site.
Connect-PnPOnline -Url "https://tenantname.sharepoint.com/sites/sitename" –Credentials (Get-Credential)

#Get the group that contains the accounts of the Managers
$group = Get-PnPGroup "VisitorGroupName of Managers"
#Loop through the users
foreach ($user in $group.Users) {

    #Check to see if folder exist and create it if it does not.
    Resolve-PnPFolder -SiteRelativePath "LibraryName/$($user.Title)"

    #Get the new folder and allfields.
    $folder = Get-PnPFolder -Url "LibraryName/$($user.Title)" -Includes ListItemAllFields

    #Remove all permission and add the Read Role to the user.
    Set-PnPListItemPermission -User $user.Title -AddRole 'Read' -List "LibraryName" -Identity $folder.ListItemAllFields.Id -ClearExisting

    #Remove the Full Control Permission for the account that is running the script.
    Set-PnPListItemPermission -User <Account running the script> -RemoveRole 
    'Full Control' -List "LibraryName" -Identity $folder.ListItemAllFields.Id 

}

For Item 3 I am at a complete loss I would like to find a way to parse the "MgrNumber" on the title of each file and move it to the corresponding folder.

I have not found much about RegEx in the SharePoint PNP comandlets.
If I have to run a separate script I am fine with that too.

Thank you