Thanks for the clarifications.
I believe reinstalling the audio driver should hopefully resolve the issue. I suggest doing so as instructed below.
Download the latest audio driver from the Lenovo website (link below), uninstall the current driver, restart your computer, and install the driver you downloaded.
https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-l-series-laptops/thinkpad-l480-type-20ls-20lt/20lt/downloads/driver-list/component?name=Audio&id=3AA7F1C4-5B2A-453C-9CE2-B8FCDA8B69BA
Driver name: Realtek Audio Driver for Windows 11 (Version 21H2 or later), 10 (Version 1809 or later) - ThinkPad L480, L580
Version: 6.0.9354.1
(Run the downloaded EXE file and follow the on-screen instructions to install the driver.)
You should be able to uninstall the current Realtek driver in "Settings > Apps > Installed apps/Apps & features". It should be named "Realtek Audio Driver" or "Realtek High Definition Audio Driver".
(If you can't find the driver to uninstall, install the driver I suggested in the link above.)
After reinstalling the driver, restart your PC and see if the audio will work properly.
If the problem persists, please let me know.
Feel free to ask back any questions.
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