Thank you for contacting us and I'd be happy to assist.
Toolset only offers a single setting to control the Gutenberg editor's width, which is already set to 100%, in your screenshot.
I suspect that the active theme or some third-party plugin is applying that padding around the content. Have you tested this with a default theme like Twenty Twenty One and with all non-Toolset plugins disabled?
If the issue still persists with the default theme and without the extra plugins, you're welcome to share temporary admin login details, along with the link to the edit screen, where this padded layout can be seen.
Note: Your next reply will be private and please make a complete backup copy, before sharing the access details.