If it helps..
Go to settings in the Side Bar Menu and choose Page Builder.
Under GENERAL, I have the following two boxes checked.
√ “Use Classic Editor for New Posts” and
√ “Default to Page Builder Interface”
Then when I go to edit a page I have the option “revert to editor” or “page builder” at the top right of editor.
You can experiment with the settings. If you have the Page Builder Interface checked, when you go to edit a page you should see a “+” symbol in the tool bar for adding Site Origin Layout.