Kurzgesagt didn't invent the concept of disassembling Mercury to build a Dyson swarm. Stuart Armstrong proposed it in a lecture in 2012[0].

[0]: https://youtu.be/zQTfuI-9jIo?si=3jwmhoB7zx6rclhb

Pretty sure the idea predates that lecture, it appears in Charles Stross' novel Accelerando from 2005 (which is based on short stories that were published years earlier).

That video is describing the generic concept of building a Dyson sphere from Mercury but lacks a proper account of waste heat removal and energy. It also lacks a specific timeline.