It is interesting that they filed for the normal lawsuit first rather than petition for an injunction to stop NewJeans activities outside of Ador, though I suspect that will eventually happen as well if NewJeans ever refuse new activities beyond their currently scheduled commitments, so if they can get a confirmation regarding validity, then they can safely file for injunction.
Either way I suppose the girls and whoever is backing them (parents, min heejin, etc) got their wish that Ador is the one suing first.
Just handwavy-analysis of this, I don't think their argument that NewJeans can't unilaterally terminate the contract will hold up in court. There's at least two standard clauses that has come out from their contract segments being reported on that very much allows them to unilaterally terminate their contract, one involves paying penalty fees, the other depends on Ador not protecting the interests of their artists. And there's the standard termination of contract when trust is broken and upholding the contract is no longer tenable, that clause doesn't even have to be in the contract for it to apply based on their contract laws.