I used this Audacity Tool on my past iNaturalist audio files to make them better.
You can right-click on them in the observation page to download them. Then, you add the new version and delete the old one in the Edit page. There’s a tab for Sounds.
I was going to do this for my existing eBird audio files. You can download your eBird audio files.
You log in and find the audio file on a checklist. Or, you can go through My eBird and list your species with audio.
There is a link to the Macaulay Library version in the bottom right part of the web page with your audio recording in a checklist. Click on that link.
On the lower right side of the new Macaulay Library web page that opens, there is a link to download it. You can then add the new recording to your checklist and delete the old one.