Is <flux:modal> implemented as a portal/teleport? If yes, the modal content is not inside the <form> DOM node → form submit/wire bindings won't work.

Do your DB columns match criteria and marks? If using AssessmentCategory::create($validated) ensure the model has protected $fillable = ['criteria','marks']; (or pass explicit array).

Include @livewireStyles / @livewireScripts and check console/network for Livewire XHRs.