Thank you for asking your question on the Microsoft Q&A platform.
As per my knowledge, we don't have any out-of-box BizTalk adapter which can directly communicate to AWS S3. You can use the approach explained by Kent in his blog or you can go with a hybrid approach. So in a hybrid approach, you can use a Logic-app adapter in BizTalk and then using function connect to AWS S3.
There are some other options are available which are described in below blog post. Kindly check, it might help for you.