You have a password field:

use Filament\Forms\Components\TextInput;
 
TextInput::make('password')
    ->password()

And you wanted to hash the password when the form is submitted:

use Filament\Forms\Components\TextInput;
use Illuminate\Support\Facades\Hash;
 
TextInput::make('password')
    ->password()
    ->dehydrateStateUsing(fn ($state) => Hash::make($state))

But you don't want to overwrite the existing password if the field is empty:

use Filament\Forms\Components\TextInput;
use Illuminate\Support\Facades\Hash;
 
TextInput::make('password')
    ->password()
    ->dehydrateStateUsing(fn ($state) => Hash::make($state))
    ->dehydrated(fn ($state) => filled($state))

However, you want to require the password to be filled on the Create page of an admin panel resource:

use Filament\Forms\Components\TextInput;
use Filament\Pages\Page;
use Illuminate\Support\Facades\Hash;
 
TextInput::make('password')
    ->password()
    ->dehydrateStateUsing(fn ($state) => Hash::make($state))
    ->dehydrated(fn ($state) => filled($state))
    ->required(fn (string $context): bool => $context === 'create')