Workflow

GitLab (fewer requirements)
Similar (because any workflow works on both systems)
Minimum hardware requirements: 4 vCPU and 4 GB RAM support up to 500 users. No specific recommendation for disk size.
GitLab proposes more workflow models than GitHub, with feature, development, production, environment and release branches. GitLab Flow is the standard. GitLab workflow is supported by merge requests (MRs), which are a framework for code review before merging.
Supporting up to 3000 users, requires 8 vCPUs, 48 GB RAM, 300 GB attached storage, 200 GB root storage.
GitHub proposes a simple workflow, which has feature branches and a main branch. GitHub workflow is supported by pull requests (PRs), which are essentially the same as GitLab MRs.