I am trying to create a list of contact and add the to the community as users. I keep getting the error:

I am trying to create a list of contacts and add these to the community as users. I keep getting the error:

I am trying to create a list of contact and add the to the community as users. I keep getting the error: MIXED_DML_OPERATION, DML operation on setup object is not permitted after you have updated a non-setup object (or vice versa): User, original object: Contact: []

public without sharing class addController {
@AuraEnabled

public static void saveContacts(List<Contact> listContact){
    Insert listContact;
    system.debug('listContact '+ listContact);
    
    User currentUser = [SELECT Id, Contact.AccountId FROM User WHERE Id =: UserInfo.getUserId() LIMIT 1];
    system.debug('currentUser '+ currentUser); 
    
    List<User> uList= new List<User>(); 
    List<Relatie__c> rel= new List<Relatie__c>(); 
    UserRole ur = [SELECT Id FROM UserRole Where name = 'Partner'];
    
    Profile profileId = [SELECT Id FROM Profile WHERE Name = 'Customer Community User' LIMIT 1];
    
    for(Contact con : listContact){
        
        Relatie__c rc = new Relatie__c(Account__c = currentUser.contact.AccountId, Contactpersoon__c = con.id ) ;
        system.debug('rc '+ rc);
        rel.add(rc); 
        string alias = con.firstName.substring(0,1) + con.lastName.substring(0,1);
        user u = New user(userName = con.firstName+'.'+con.lastName+'@test.nl' ,
                          firstName = con.firstName, 
                          lastName = con.lastName, 
                          alias = alias, 
                          email = con.Email, 
                          communityNickName = alias, 
                          timeZoneSidKey = 'Europe/Amsterdam', 
                          LocaleSidKey = 'nl_NL', 
                          EmailEncodingKey = 'ISO-8859-1', 
                          LanguageLocaleKey = 'nl_NL', 
                          ContactID = con.id,
                          ProfileId = profileId.id,
                          UserRoleId = ur.id
                         );
        
        uList.add(u); }
    insert rel;
    system.debug('rel '+ rel);
    insert uList;
    
}

}

I am trying to create a list of contact and add the to the community as users. I keep getting the error:

MIXED_DML_OPERATION, DML operation on setup object is not permitted after you have updated a non-setup object (or vice versa): User, original object: Contact: []

public without sharing class addController {
    @AuraEnabled
    
    public static void saveContacts(List<Contact> listContact){
        Insert listContact;
        system.debug('listContact '+ listContact);
        
        User currentUser = [SELECT Id, Contact.AccountId FROM User WHERE Id =: UserInfo.getUserId() LIMIT 1];
        system.debug('currentUser '+ currentUser); 
        
        List<User> uList= new List<User>(); 
        List<Relatie__c> rel= new List<Relatie__c>(); 
        UserRole ur = [SELECT Id FROM UserRole Where name = 'Partner'];
        
        Profile profileId = [SELECT Id FROM Profile WHERE Name = 'Customer Community User' LIMIT 1];
        
        for(Contact con : listContact){
            
            Relatie__c rc = new Relatie__c(Account__c = currentUser.contact.AccountId, Contactpersoon__c = con.id ) ;
            system.debug('rc '+ rc);
            rel.add(rc); 
            string alias = con.firstName.substring(0,1) + con.lastName.substring(0,1);
            user u = New user(userName = con.firstName+'.'+con.lastName+'@test.nl' ,
                              firstName = con.firstName, 
                              lastName = con.lastName, 
                              alias = alias, 
                              email = con.Email, 
                              communityNickName = alias, 
                              timeZoneSidKey = 'Europe/Amsterdam', 
                              LocaleSidKey = 'nl_NL', 
                              EmailEncodingKey = 'ISO-8859-1', 
                              LanguageLocaleKey = 'nl_NL', 
                              ContactID = con.id,
                              ProfileId = profileId.id,
                              UserRoleId = ur.id
                             );
            
            uList.add(u); }
        insert rel;
        system.debug('rel '+ rel);
        insert uList;
        
    }
}