Dell XPS 17, intel 11th gen, 9710, with KDE Plasma

Dear mates!
My laptop is only few months old but my left speaker broke and makes this awful sond. I try to keep it from the Settings / Audio / muted but after some short time automaticaly the balance changes and I start hearing it again.
My question is how to permanently mute the left speaker until I get it fixed in the future?

Open the case and cut the wires to the left speaker. Permanent.

Dell XPS 17 9710 has a Realtek ALC711-CG audio codec and 2 ALC1309D mono amplifiers for headphones/speaker outputs. Most Realtek codecs have one audio control for both speaker channels but this device has independent controls for left and right channels

amixer --card=1 sset 'rt1308-2 DAC L' toggle

If that turns off left channel for Headphones rather than Left Speaker, run the command again to toggle headphone channel back on, and use this command to turn off the left channel on the first DAC output

amixer --card=1 sset 'rt1308-1 DAC L' mute

HW probe of Dell XPS 17 9710: amixer