can this KPOP line up fill up the stadium ?

Not sure. I feel like 20k at most.

They might

no, 25k max

wow they are coming to Warsaw and on stadium???

Mamamoo couldn't fill up arena's and G Idle failed to fill up a mix of halls and theaters.

But together with several BG's...the stadium might only be 30-ish thousand. So probably each fandom only has to bring in 3k fans each and the general local Kpop fans will likely have some interest too...I would say yeah, probably. Unless it's a stadium like SoFi or Wembley and we're talking 50-60 thousand...not a chance.

should also post the ticket prices to give better context

Looks like a massive uphill battle