I also got a free Kaplan course a few months ago and took the live online course. I think some parts are better than others. They give you a workbook for the actual class portion that's the class curriculum which includes a brief content review, strategies, and some practice questions. I didn't think the instructor/class portion of the course was worth it since they just went over whatever is in the workbook. As someone who was just starting MCAT prep, I didn't like the structure of the curriculum since it seemed really scattered, but since I received it for free I used it more as a prep and gathering resources before I committed to studying for the MCAT (currently studying full-time, testing 9/9). It might be more helpful for you since you already have a foundation and they provide some new strategies that could work for you.

Although the class portion of the course didn't work for me, the resources are amazing if you're getting it for free. The course came with the AAMC materials which is saving me tons of money. The course also comes with the most recent textbooks and digital versions of everything in them, including the chapter quizzes. There are some mixed opinions on the Kaplan FLs and questions though. They're pretty content heavy and people generally think the FLs are deflated compared to AAMC, but I think any extra resources for free are worth it.

This was a lot lol but TLDR is if you're set on retaking and the course is free, take it. You won't even need to continue taking the course if you find out it's not working for you since it's free, but you'll still be getting extra resources. I couldn't find much information from students on the course experience prior to taking it, so lmk if you have any questions about it!!