I can’t think of anything else to try. I wasn’t even sure if the registry update would work. Are there any other files in the monitor location that might still be exceeding the 260 character limit?
Try running the following in an Admin Powershell to output the path to everything under the folder and the length of the path sorted by longest to shortest.
Get-ChildItem -Path "\\192.168.1.77\Media\tv" -Recurse -Force | Select-Object -Property FullName, @{Name = "FullNameLength"; Expression = { ($_.FullName.Length) } } | Sort-Object -Property FullNameLength -Descending