Usually when we speak about Microservices architecture we find message broker like RabbitMQ or Kafka.
But, in my current environment they already have BizTalk. From my understanding of BizTalk should do the job. So my question is more from a Best Practices point of view. It's easy to find comparison for RabbitMQ and Kafka, there isn't much on BizTalk.
I've made some use of BizTalk in a previous job and RabbitMQ at my current. While it's possible to use BizTalk for that purpose, it's not typical (according to Microsoft).
There's some value in reusing what you already have, but in my experience there's way less overhead using RabbitMQ. It's simply a message broker and doesn't not a dozen other things as well, like BizTalk. It brings a lot of possible issues and, as you've seen, limited information as support from a general search.
Unless you are interested in using the transformation/repair/etc options BizTalk provides, I wouldn't recommend it. As far as I know it's usually used to facilitate communication with legacy or external software. And even then, if you're using microservices, you could always make another one for that purpose.