What limitations exist when using a standard queue in queue systems?

Standard queues (for example, in iOS, DispatchQueue) have several limitations:

• Execution order: a standard serial queue executes tasks strictly in order, which can become a bottleneck when parallel processing is needed.
• Lack of priorities: in a standard serial queue, tasks are executed in the order they are added, without the ability to set priorities.
• Blocking: if a task takes a long time, it blocks the queue, delaying the execution of subsequent tasks.
• Resource limitations: too many tasks in the queue can lead to increased memory consumption.