I'd also say that gitlab runners are the biggest failure point in gitlab and take some work to micro-manage. If I was setting up from scratch I would consider gitlab for source control, but some hosted service for CI

Maybe give https://rocketrunner.io a try? We made super easy and fully managed GitLab CI/CD runners for GitLab.com or self-hosted GitLab servers :-)

(Sorry for posting this twice, but we'd really love to get more user feedback)