Everything in “Program Files” has been installed, rather than just extracted.
Audacity is available as “.zip” files, (e.g. “audacity-win-3.2.1-64bit.zip”),
which can be extracted into its own folder, which you create.
Such extracted Audacity versions are independent from each other,
whereas installed versions will share the hidden audacity file, with disastrous results.
Re: https://youtu.be/yHx3ErLE9x4.
Transcoding by YouTube can increase sibilance.
If you want to preemptively reduce it, the free desibilator plugin does a good job
If your audience is the same vintage as John Travolta they may benefit from leaving sibilance it as is:
high-frequency hearing will have noticeably diminished by that age.