The girls could probably go to almost any of the big international music companies. The companies may be willing to spend huge amounts of money to sign the girls, but there is one thing they definitely cannot give them: use of the "Blackpink" brand/IP, including everything associated with it, like their lightstick design.
The girls are individually big, but Blackpink is bigger, so losing the ability to use the brand would hurt.
My opinion: there is nothing that even UMG, or a similar company, can offer (that YGE can't) that could compensate for the loss of the use of Blackpink IP, even if they had no interest in working as part of the group and went 100% solo. The only exception would be if they (Jisoo) left the music industry entirely to pursue other things (acting), but even in that case the brand would still be valuable.
Of course, they could dislike working in YGE so much that they leave anyway, or work out a contract with YGE that allows them to use the IP, but YGE could charge a ton of money for that if they are willing to let the new company use the IP at all.
