Remove Full Access permissions from shared folders with exceptions - powershell

Question

Basically at my new work we have a shared network area with individual folders for each department. Each folder has multiple sub folders. The problem is the previous manager assigned 'full access' security rights on each folder and subfolder to absolutely everyone, including the 'everyone' group. I'd like to change the 'full access' security permissions for modify, but not for certain security groups like domain admins and certain other security groups.
I have some code in PowerShell that gives me a list of which groups have full access permissions but I need to be able to take that list and change them to modify.
This is what I shamelessly stole and modified from someone else.
$path = "\\srv-shared\sharedfolders"
$ExcludeUsers = 'Domain\Domain Admins',
'NT AUTHORITY\SYSTEM',
'BUILTIN\Administrator',
'domain\Administrator'
# Create regex-pattern to match all excluded users
$ExcludeUsersRegex = ($ExcludeUsers | % { [regex]::Escape($_) }) -join '|'
Get-Childitem $path -Recurse -Directory | ForEach-Object {
$file = $_
Get-Acl -Path $file.FullName |
Select-Object -ExpandProperty Access |
Where-Object {
$_.IdentityReference -notmatch $ExcludeUsersRegex -and
$_.AccessControlType -eq "Allow" -and
$_.FileSystemRights -eq "FullControl"
} | ForEach-Object {
#Foreach ACL
New-Object psobject -Property #{
Path = $file.FullName
ACL = $_.IdentityReference
}
}
} | Select-Object -Property Path, ACL | Export-Csv e:\check_acl.csv -NoTypeInformation
Basically in the #Foreach ACL section i need it to change the full access permission for the group/user its just found and change it to modify instead.