On Laserdiscs where there are dropouts and the sound sounds like bacon crisping in a pan, you cannot really do anything can you?
Years ago i tried to capture a rotted title and even with software i couldn’t restore the sound even with filling in gaps from another source.
It simply was easier to get the VHS or DVD counterpart and use the audio from those.
I still hope you can find a solution on how to capture the DiscoVision audio.