I originally wrote specific terraform providers (even one for just configuring an Ubuntu machine), but over time I found that TF is a bit too heavyweight for my use-cases. The shell script works well because state divergence can be investigated by the LLM. The slowness of state refreshing etc. does make a TF apply painful. For me at least.

How big is your TF state on your routers?

Yeah, TF is slow if you have thousands of configs and batching not integrated in the provider.