Hello, Timothy! There could be a couple of reasons that the playlist is reappearing. One of them being it could be syncing from the cloud, so it's appearing that way.
The second reason it could be stuck in the temporary files on the phone somehow. You can try after deleting it to wipe your cache partition and see if that will make any changes:
Turn off the device.
Press and hold the Volume Up key and the Bixby / Power key.
When the Android logo displays, release both keys.
An 'Installing system update' message may show briefly before the Android Recovery menu options appear.
Press the Volume down key several times to highlight Wipe cache partition.
Press Bixby / Power key to select.
Press the Volume down key to highlight Yes, then press the Bixby / Power key to select.
When the process is complete, Reboot system now is highlighted.
Press the Bixby / Power key to restart the device.
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