I’m not an expert, either (I only ever took one grad course in string theory). From what I know, you are correct, the two are independent, though there are some string-based proposals for inflation or something like it. For example:
an interesting proposal for pre-Big Bang cosmology where the stringy Universe starts out flat, cold and very large instead of curved, hot and very small. This early Universe is unstable and starts to collapse and contract until it reaches the self dual point, where it heats up and starts to expand to give the expanding Universe we observe today.
How do string theories relate to inflation models? They seem orthogonal, but I’m a total layman in the area.
I’m not an expert, either (I only ever took one grad course in string theory). From what I know, you are correct, the two are independent, though there are some string-based proposals for inflation or something like it. For example: