This can be true, but I would argue not always. Some DevOps teams work in the old mode of “throwing code over to Ops to run” - this isn’t what DevOps intended, but happens.
When they work well, they’re doing things like authoring reusable (by product eng. teams) infrastructure modules, or helping to build “you build it, you run it” tooling like monitoring stacks etc. They’re also helpfully/hopefully subject matter experts on CI/CD, your cloud/hosting of choice, security stuff - things that general developers have mixed levels of interest or competence in.
When they work well, they’re doing things like authoring reusable (by product eng. teams) infrastructure modules, or helping to build “you build it, you run it” tooling like monitoring stacks etc. They’re also helpfully/hopefully subject matter experts on CI/CD, your cloud/hosting of choice, security stuff - things that general developers have mixed levels of interest or competence in.