Improvement of the Bank Queuing System

I believe you have similar experiences with me. There are a lot of people working in the bank. If you have an electronic queuing system, you can sit and wait. Theoretically it should be good, but think about it carefully, there are still many problems.
The electronic queuing system is like this, that is, the customer first obtains a queuing number on the electronic touch screen at the door, and then waits for the number to be called. Bank staff (for example, three) Click the bell to call the next number after processing a business.
In theory, this should be a good way. After you get the number, you can proceed to handle the business. If you do not call it, you can continue to wait. It is fair and fast. But in fact, this is only a good way in theory. Due to human factors, this method still has two major problems.
First, because there are too many people in the queue, some people may leave after they get the number, or some people may frequently get the number to wait for someone. That is to say, many of the queuing numbers are actually empty. This makes it possible for a bank employee to call the number two to three times when no response is received. If no response is received, the bank employee will press the next line number. I remember one time, I was waiting in the queue. No one had even pressed the five numbers for the bank staff to come forward. The customers we sat down with looked around every single number. Even if no one goes forward, it means there are fewer queues. However, the constant calling of empty numbers is a waste of time by others, which still makes people feel uncomfortable.
Second, most bank employees work very seriously. Every time a business is completed and a customer is served, the next number is called by the bell. However, there are also a few friends who take advantage of this opportunity, usually after a business is completed, they will wait, such as more than ten seconds, slow or even minutes. The feeling is that he is using this gap to take a break. Although the rest is understandable, there are still dozens of people waiting anxiously outside, and you are too slow.
Let's look back at the banks that do not have an electronic queuing system. because they do not have this high technology, they all have to queue honestly. However, after completing one operation, we will go on to the next step. The customer will not let the bank staff rest, but leaving in the middle means giving up the queue, so it seems that everyone is waiting in the queue, even standing, very hard, however, time is saved.
Why does the high-tech electronic queuing system solve the problem of fair queuing, but there is still a waste of time? Is there a better solution?

I have come up with a solution. In fact, the improvement of the electronic queuing system can completely improve this time-wasting situation and save installation costs.
It is easy to say, that is, to combine a queuing system and a non-queuing system. That is, the actual bank counter staff are not allowed to ring the bell, but the Hall security guards or other staff are allowed to ring the bell to ensure that five people are waiting in front of the queue for business handling, the customer who has not called the number continues to rest or wait in any position in the hall. As a result, five people are always waiting for business operations according to the number. If there is a blank number among the waiting persons, the security guard will press number 1 to queue up. The biggest benefit of doing so is to push forward the call process and confirm whether there is any blank number before handling. Since there are always about five customers waiting for business processing, the bank staff have no time to be lazy. This solves the two problems I mentioned earlier. In addition, because you do not need to install the bell-pushing device in each counter, the cost is actually reduced.
Maybe you still have a better solution. I just want to discuss it.