Is there any way to trigger the ci/cd pipeline without using .gitlab-ci.yml file?

My situation is like this: I have many projects to manage. Whenever I want to modify the deployment process, I need to enter each project separately and modify .gitlab-ci.yml file of the project, which is too unfriendly for me.

I wonder if there is a way to manage all .gitlab-ci.yml files in one project? Then, when each project executes CI / CD, get the .gitlab-ci.yml file from the project?