If there are multiple Scrum Teams working on the system or product release, the Development Teams on all the Scrum Teams must mutually define the definition of "Done". Each Increment is additive to all prior Increments and thoroughly tested, ensuring that all Increments work together.

A person or team working on a single problem at a time is typically more effective than one that is working on multiple problems congruently as they can fully focus and dedicate their energy to resolving the problem before moving to the next. Having a well-structured Product Backlog can help minimize dependencies and increase focus for each team.

The highest priority is to satisfy the end users.

Many people misinterpret the Scrum Guide as stating the Development Team size is limited to 3-9 members.
In reality, it only states that there is inherent risk attached to having less than 3 members and more than 9 members. As the number of members increases, the lines of communication also increase. This can be calculated using the Group intercommunication formula: n(n − 1) / 2 where n is the number of members.
Some teams are able to handle the risk and "synergize" whereas others might struggle. Saying that, the relationship between defining a Sprint Goal and Development Team size is unclear.
But the relationship between the ordering of the Product Backlog, the PO having clear objectives, and the Sprint Goal are direct. The Product Owner typically comes to the Sprint Planning with a business objective in mind and Product Backlog items related to the business objective. After deciding what can be done for the upcoming Sprint, the Scrum Team will craft a Sprint Goal that would be met through the implementation of the items. This is not dependent on the size of the team nor length of the Sprint.
Scrum is also a framework that's fit for purpose. Some projects/products are not fit for Scrum... or, better stated, Scrum is not suitable for all projects/products.

Explanation
Explanation:
Product Backlog items should be clear enough and have enough information for the Product Owner and Development to understand the work that needs to be done and to create a forecast of Product Backlog items to implement the Sprint Goal. Nothing stops the flow of Sprints, for example, we do not delay the Sprint because the items are not ready. In such cases, the "unready" items would be selected for the Sprint anyway and refined during the Sprint.
In the case that the Product Backlog items are not clear enough, the Development Team forecasts the most likely Product Backlog items to meet the goal and create a Sprint Backlog based on a likely initial design and plan. Once the time-box for the Sprint Planning meeting is over, start the Sprint and continue to analyze, decompose, and create additional functionality during the Sprint. At the end of the Sprint, the Scrum Team can discuss in the upcoming Sprint Retrospective why this happened and what changes will make it less likely to recur.