I found a solution from Thomas Frank, a YouTuber that provides a lot of information about Notion. He has a script you can download, that converts audio recordings to text, using Whisper AI, and that places the text (plus selectable features like summaries etc) in a Notion database. The cost is very low! Even a half-hour recording comes in at pennies.
Plus, Adobe Premiere Pro video editing software has a built-in transcription function (to create sub-titles), that seems to work pretty well, and costs nothing per use.