Before deleting the project, it must be archived first.
As the next step you have to open the archived project:
After this step, the archived project will no longer be used for any calculations.
You will only see an option for deletion after archiving the project.
NB! Deleting the project is possible only for users with Company projects admin role.
To see who to contact with deleting, navigate to project Settings and take a look at the "Roles" column in the "Users with project access" table.