> 10 years worth of monthly meetings

if it's 1 monthly video and thus 120 videos (or so) you could try recall (getrecall.ai not recall.ai that is a similar product with a similar name). They summarize youtube videos, but you get the transcript. AFAIK you cannot batch the processing and you have to add each video one by one, that's why 100 or 200 videos is doable but probably not thousands.