According to the SAFe 6 Scrum Master documentation, one of the ways a Scrum Master/Team Coach can help improve ART performance is to facilitate cross-team collaboration. Cross-team collaboration is the ability of Agile teams to work together effectively and efficiently to deliver value to the customers and stakeholders. It involves sharing information, resolving dependencies, aligning on goals, and providing feedback. Cross-team collaboration is essential for achieving the ART vision and objectives, as well as for delivering integrated and high-quality solutions.
The Scrum Master/Team Coach plays a key role in facilitating cross-team collaboration by 1:
Participating in the Scrum of Scrums (SoS) and ART Sync meetings, where they communicate the team's progress, impediments, and dependencies, and coordinate with other teams and the Release Train Engineer (RTE) Helping the team prepare for and participate in the PI Planning event, where they collaborate with other teams to define and commit to the PI objectives and identify risks and dependencies Supporting the team in the System Demo, where they demonstrate the team's work to other teams and stakeholders, and receive feedback and validation Assisting the team in the Inspect and Adapt (I&A) event, where they review the ART performance, identify improvement opportunities, and create action plans Encouraging the team to adopt Communities of Practice (CoPs), where they share knowledge, best practices, and learnings with other teams and experts Promoting a culture of trust, respect, and cooperation among the team and other teams (Must be taken from SAFe 6 Scrum Master resources) Reference:
Scrum Master/Team Coach
Team Sync
PI Planning
System Demo
Inspect and Adapt
[Communities of Practice]

The primary goal of a team in an Iteration is to deliver working functionality that meets the acceptance criteria and the definition of done. This functionality is demonstrated to the stakeholders and customers in the Iteration Review and Demo event, where the team receives feedback and validation. By delivering working functionality at the end of the Iteration, the team contributes to the Incremental value delivery, one of the SAFe Lean-Agile Principles. (Must be taken from SAFe 6 Scrum Master resources) Reference:
Iteration Goals
Iteration Planning
Iteration Review and Demo

One of the responsibilities of a Scrum Master/Team Coach is to help the team achieve flow, which is a state of continuous and sustainable delivery of value. They do this by teaching and coaching the team on SAFe Scrum and SAFe Team Kanban practices, such as limiting work in progress, visualizing work, managing queues, and reducing batch sizes. They also help identify and eliminate impediments and bottlenecks that hinder the team's progress and performance.
Reference:
Scrum Master/Team Coach - Scaled Agile Framework
Exam Study Guide: SSM (6.0) - SAFe Scrum Master

One benefit of PI Planning is that it allows for faster decision-making by bringing together all the members of the Agile Release Train (ART) and the relevant stakeholders in a face-to-face (or virtual) event. PI Planning provides an opportunity for the ART to align on a common vision and mission, review the business context and priorities, identify and resolve dependencies and risks, and commit to a realistic and achievable plan for the next Program Increment (PI). By having everyone involved in the planning process, the ART can leverage the collective knowledge and expertise of the participants, reduce ambiguity and uncertainty, and make informed and timely decisions that support the delivery of value to the customers. (Must be taken from SAFe 6 Scrum Master resources) Reference:
PI Planning - Scaled Agile Framework
Planning Interval (PI) - Scaled Agile Framework
Preparing for PI Planning | Checklist for Scrum Masters and Product ...
Scrum Master - Scaled Agile Framework
Scrum Master role in PI Planning - ValueGlide

The first step of the problem-solving workshop is to agree on the problem to solve. This step is important because it helps the teams to clearly state the problem, highlight the what, where, when, and impact of the problem, and avoid addressing the symptoms instead of the root causes. By agreeing on the problem to solve, the teams can focus their investigation and analysis, and save time and effort. The problem statement should be succinct and specific, and should not include any assumptions or solutions.
Reference:
Inspect and Adapt - Scaled Agile Framework
Problem-solving workshop: Step-by-Step - Agilephoria
The Sun Never Sets on the Problem-Solving Workshop