I try to set default settings but no matter what it is it still stays on the original default setting

Are you using carpetskyadditions setDefault [rule] [value]? The settings system is managed by Carpet so this is likely a Carpet issue, not an issue with this mod. Can you change the Carpet defaults with carpet setDefault [rule] [value]?

Hi, I have same problem like Floppa26 and idk how to fix it. Can u give me some tutorial? thanks a lot

To set the defaults, you need to use the carpetskyadditions setDefault [rule] [value] command.
Something like carpetskyadditions setDefault renewableSwiftSneak true should work.

Gnembon's video explains how carpet works in his tutorial video here: https://www.youtube.com/watch?v=Lt-ooRGpLz4. The first few minutes should tell you all you need. This mod is an extension to carpet and uses the same settings system, just with the carpetskyadditions command instead of carpet.

In single player with cheats disabled, you'll need to open your world to LAN to allow you to use commands.

Alternatively, you can edit carpetskyadditions.conf in your world folder and add lines like renewableSwiftSneak true.