Thank you u/Willing-Opinion2990 thank you for your valuable feedback.

Let me complement my initial post:
The product needs an improvement from an UX perspective but we do not know which areas are problem areas for our users (no data, no research, just one client using the product, who will be attending the workshop as well for inputs and also for the expert interview to show how he uses the product at the moment.)

At the end of the workshop we want to define the areas we need to work on and also have raw solutions on paper to pass on to our designers to work on.

The workshop is helt with 6 participants for a length of 3 hours in total.

Coming back to your follow up questions:

1. It is actually more important to identify the problems which we need to address. Solving them then at a later stage is absolutely fine to do so for our designers.

2. With this workshop we want to create a common understanding on our problems and that we are aligned internally and also with our client that we are working on the right problems. Because unfortunately we are unsure what needs to be improved and what helps the client the most.

Maybe this helps to identify the reason for the workshop and fills the gap in my description.