Hi @CGW!
For large lists of targets, the most efficient way to query the data is to use our data downloads.
Our amazing Irene Lopez created a parallel post to walk you through this: Get marketed drugs for a set of targets with the data downloads
Here too, there is some information available in the documentation.
For target-disease associations, we have a number of download files available, depending on the information you are looking for. Check out the files we have available here: Open Targets Platform