You’re doing it right by avoiding as much of Gitlab’s CI features. I’ve seen versions where scripts are inlined in the YAML with expressions in random rule fields and pipeline variables thrown all over the place. And don’t get me started on their “includes” keyword, it’s awful in practice, gives me nightmares.
Then I write a Kubernetes manifest in YAML with JSON schema validation and the heart rate goes down again.
Abstractions aren’t concrete and all of these standards you’re referring to are concrete data serialisations. You may be interested in CUE which captures this concept in its design.