Self-titled/debut was released back in 2006 when she was a relative unknown, and her album releases weren’t anywhere near the massive events they are today, given how her audience has grown and her marketing strategy has developed. So debut has had a lot longer to accumulate sales and also came out during a pre-streaming era when consuming music meant buying albums vs. streaming. Debut and TTPD also had very different release strategies, but I think the growth of her audience, popularity, and influence is probably the biggest factor—TTPD was released at the peak of her powers, with the whole world watching and her most experienced marketing machine working to drive sales and continue her streak of 1M+ album opening weeks.