Is it possible for a Weki Meki, Pristin, gugudan or GWSN song to suddenly make it to the top charts?

I don’t think so, such a comeback seems to require visibility on korean media and a strong fandom.

i could single handedly make pristin chart

I mean EXID did it (better than Brave girls because they made a sustainable career out if up & down) so its possible but they would need to make a huge splash with a performance

yes

first they would need to reform

second they would need to coordinate a producer/song/performance etc etc

and they would need to defy all previous expectations to get a chart topping song which is so improbable that it might be considered impossible