Gitlab CICD pipeline conversion to Jenkins (Production ready kubernetes cluster)

Hi All, Currently, we are using Gitlab CICD pipeline (gitlab runner is deployed in Kubernetes cluster on an on-prem server). The pipeline is for a microservices project having test/dev environment and .gitlab-ci.yml is placed in every microservice folder. I would like to know what is the best approach suitable for production to replicate this pipeline in Jenkins step-wise if anyone has experienced the same situation before.

  1. Better to install Jenkins in k8 cluster or separately?
  2. How to easily convert .yaml file to Jenkins file?
  3. Deployment approaches:
    3.1 Deploy though Helm chart in k8 cluster using jenkins?
    3.2 Use Argo CD for deployment?
    3.3 Or Use Ansible or any other recommended method.