Validation in update (store would be the same, but without unique ignore) - see: https://learntech.imsu.ox.ac.uk/blog/angular-reactive-form-custom-validator-for-orcid/

UserController.php

 public function update(Request $request, $id)
    {
    
		$messages = [
      			...,
			'orcid.unique' => 'This ORCID ID is already in use in our database',
			'orcid.regex' => 'The ORCID ID is in the format https://orcid.org/xxxx-xxxx-xxxx-xxxx',
      			...,
		];
		
		//require more complex validation style to have unique ignore rule for ORCID
		Validator::make($request->all(), [  //request->all() returns array required by Validator::make
			...,
			'orcid' => [
				Rule::unique('users')->ignore($id),
				'regex:/^http[s]?:\/\/orcid.org\/(\d{4})-(\d{4})-(\d{4})-(\d{3}[0-9X])$/',  //from: https://github.com/pkp/pkp-lib/blob/master/classes/validation/ValidatorORCID.inc.php
				new Orcid
			],
			...,
		],$messages)->validate();