I think it will be more realistic if certifications combine pure sales and streaming sales for example:
Sorry Not Sorry - Demi Lovato
Pure Sales: 234.000
Streaming Sales: 266.000
SPS: 500.000 (GOLD)
Part of Me - Katy Perry
Pure Sales: 495.000
Streaming Sales: 505.000
SPS: 1.000.000 (Platinum)
We Belong Together - Mariah Carey
Pure Sales: 3.550.000
Streaming Sales: 6.450.000
SPS: 10.000.000 (Diamond)
And you can adjust it your way
E você pode ajustá-lo como quiser