How to prohibit access to a view if the user is not the user in the account path?
The submitted by is not an access will not do it
I will post all the steps below since I am not sure what you have done (your view is translated in french)
Basically you will have a view of webform submissions with relationship to the user and filter the current user
creating the view

adding the user relationship

adding the current user filter

the finished view with important parts highlighted

the current logged in user should see ONLY their submissions NOW