I'm not sure what you are asking. What 'original layout' are you asking for?
Are you asking if there is an "undo" function on Scene/Source settings (of an unknown/large/long history/ depth)? if that is your question, my answer is 'not that I'm aware of'. I'm not aware of even a single level undo on Source settings. But do NOT take my word for it, I defer to those far more knowledgeable than I
You can create a new scene / delete current scene/sources and start over... but you probably aren't asking for that, right? did you back up your Scene settings previously (Scene Collection Export)?