rosrun/roscd not recognising correct folder/project path

edit

I made an executable python script for the nodes, and saved it at the location: /home/florian/catkin_build_ws/src/dlc_project/scripts

1. I have made it executable with chmod +x
2. I have the shebang line on top

But when I type:

roscd dlc_project

I find myself at : /home/florian/catkin_build_ws/install/share/dlc_project, instead of the dlc_project I need (inside ../src/..) Why does this happen? Any way to change this back to recognise the correct dlc_project folder.

Other details: I use catkin build (instead of catkin_make), Using Python3 + ROS Melodic + Ubuntu 18.04

Thank you!

P.S:

echo $ROS_PACKAGE_PATH /home/florian/catkin_build_ws/install/share:/home/florian/catkin_ws/src:/opt/ros/melodic/share

The reason I'm sourcing from /install is because I want to use ROS1+Python3+Cv_bridge and I am following the accepted answer here : SO answer

The line: source install/setup.bash --extend, is probably causing this. But I need to do that so that the Cv bridge built with Python3 is added to the environment. After this, how do I ensure that my project is recognized by ROS as a ROS package?