Best Methods to Analyze 400 Meeting Transcripts for Insights

Hi everyone! I have close to 400 meeting transcripts (in json format) that i would like to analyze. That is, to look for correlations between the transcripts: themes, people, needs, issues, decisions, etc. what would be your recommendation to best exploit this data. Make sure the llm can handle such a large quantity. What do you think is the best way of proceeding: combine all the transcripts into a single file, or separate them, put them in a folder, convert them into another format...?