The only valid answer is Taylor.
She destroys Rih WW album sales with only 5 albums, her tours are waaaay bigger, sold more singles in the US, is bigger than Rih everywhere except in Europe (although Tay is huge in the UK now, the biggest Eu market), and has a ton of records.
And the fact that Taylor has 3,5 albums which are country and just keeps getting bigger and bigger.

1989's sales outside the US already surpassed Unapologetic's. By the next era, the answer will be even more clearer.