How to prevent duplicate record without using Apex Trigger in Salesforce?

It works well, but if I have 50k records this impacts scalability and not feasible.

trigger duplicate on Account (before insert) {
    List<Account> acc = new List<Account>();
    acc = [Select id, Name from Account];
    for(Account a:Trigger.New){
        for(Account a1:acc){
            if(a.Name==a1.Name){
                a.Name.addError(‘Name already Exist ‘);
            }
        }
    }
}

Go to Quick Find, type duplicate Rules , untick the old rules or create a new Rule which defines duplicate not allowed