If you want to load your theme.css file inside Gutenberg editor you need to create special function for that.
Create one file that has CSS/SCSS and write your theme style there.
Then you will need one more code block to load styles css inside Gutenberg editor
Create Code Block and assign Trigger location > Everywhere

If you are using SCSS your file name will be “33-header-compiled.css”
If you are using SCSS your file name will be “33-header.css”

SCORG_UPLOADS_URL_CSS
is path our predefined path to: wp-content/uploads/scripts-organizer/css/