Jennie solo vs rose on the ground, who's solo debut was bigger hit

By sales Rose by far.

But it seems that Solo was more viral, I saw more people/idols dancing to solo on TV shows.

They were 2 different type of songs.

Considering the popularity, domestic and international acknowledgement, and fandom size of Blackpink in 2018 vs 2021...Solo.

You have to allow for inflation in terms of exposure and fandom. Same thing as the conversation around YouTube member channel subs. Solo was bigger for its time. But I think OTG would still be more successful internationally because it's in English.

OTG is breaking all kinds of records, it’s been absolutely huge! Both were very successful though.

solo in korea and on the ground globally

Solo was very successful in Korea she broke all the charts and got Paks whereas rose has broken records with physical sales for a solo artist and has more international appeal you can say. so imo both have different markets.