No it is not "just status code":

Successful responses (200 – 299) Client error responses (400 – 499)

https://developer.mozilla.org/en-US/docs/Web/HTTP/Status

I am not monitoring it per se - but all the tooling we use counts it as an error.

My endpoint is not lying - request is a question "Is there an entity B linked to entity A" - hence answer is always there and it is either "true" or "false", I am not requesting "give me entity B with Id xyz", that is a different endpoint that can return 404 nor prob.