I've not read through more than the 1st three posts so may be regurgitating...
Lots of software available to rip audio, (strip the audio from the packet/codex/container), from a video is available & free. I use one all the time.
I always rip to .wav so I don't introduce much in the way of artifacts in my work flow.
MANY Utub videos are uploaded with heavily compressed audio and video...most users take the default options when rendering a video to upload and that means 192 MP3s...the noise, if not in the original recording, starts there. Reaper, and other DAWS, convert the MP3 to a preferred format behind the scenes, much like BIAB converts WMV to .wav for use.
Which MP3 algorithm used is an issue as well...all converters have a finger print and some leave larger smudges than others.
As to removing the noise...that's really problematic. Is it heard in the video form? Have you tried other rippers/converters? Can you find it on an section of otherwise sound free ripped file? If it can be isolated then it can, more or less, be filtered out.
I occasionally have this problem when working with a friend who insists on sending me his parts as MP3. I use a freq analysis VST to work out where the worst of the sound is focused and then automate some EQ to address that freq. only when it happens. IF you have a GOOD de-esser, (the sort that is part compressor and part EQ), you may be able to dial that in to address the issue.
IF there's no gremlin in the video then you know it's part of your processing and you can address it as mentioned way above.
Good luck.

Last edited by rayc; 08/18/23 01:01 AM.
Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe