How does a runner really work?

GitLab CI/CD
1

Hello,
My .gitlab-ci.yml file is as follows:

include:
  - local: '.Project1.yml'
  - local: '.Project2.yml'

And the YAML files are as follows:

stages:
  - build
  - deploy
build-Project1:
  stage: build
   script:
    - rm -rf /data/project
    - cd /data/
deploy- Project1:
  stage: deploy
  script:
    - cd /data/docker
    - docker compose up -d

And:

stages:
  - build
  - deploy
build-Project2:
  stage: build
   script:
    - rm -rf /data2/project
    - cd /data2/
deploy-Project2:
  stage: deploy
  script:
    - cd /data2/docker
    - docker compose up -d

I have a few questions and please answer them by number and clearly:

1- For example, a change is made in Project2, because I have used include in Runner, does this cause the build and deploy steps for Project1 to be done again?

2- If I want to manually re-run the Runner just for Project1, can I do that using the Pipeline section?

Cheers.