According to the PMBOKGuide - 7th edition, project artifacts are designed to keep the project work aligned to project requirements and business goals1. However, they are not the outputs or deliverables themselves. The guide emphasizes that while artifacts are important for project management, they are not substitutes for the actual deliverables of the project1. Therefore, the project manager should advise the team that focusing only on artifacts will not lead to the successful completion of project deliverables. Instead, the team should balance the creation of artifacts with the progress of actual deliverables.
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PMBOKGuide - 7th edition1.
Business Analysis Artifacts and Treasures | Geniusee2.
Business Analyst Artifacts: Definition and Types | Apiko Blog3.

When a key team member is unexpectedly absent, it's important for the project manager to collaborate with the rest of the team to assess the impact and reprioritize tasks. This is in line with agile principles, which emphasize team collaboration and self-organization1. The team should collectively decide how to redistribute the workload, possibly by sharing responsibilities or adjusting the iteration's scope. This approach maintains the team's agility and ensures that everyone is on board with the revised plan, fostering a sense of ownership and commitment to the project's success.
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PMBOKGuide - Seventh Edition2
Professional in Business Analysis (PMI-PBA)3
ExamTopics discussion on PMP topic1

One of the ways to ensure success in a project is by motivating team members. As the project progresses, stress levels increase, and overall, things turn hostile. All this reduces the motivation of the team1. One of the crucial reasons behind project success is high project team motivation. Organizations with higher-than-average levels of employee engagement see 27% higher profits, 50% higher sales, 50% higher customer loyalty levels, and 38% above-average productivity1. Therefore, initiating rewards and incentives according to assessment results can be an effective way to encourage the team and boost their performance. References:
https://thedigitalprojectmanager.com/projects/leadership-team-management/project-team-motivation/

The project manager should have prioritized blockers on the critical path. The critical path is the sequence of activities that must be completed on schedule for the entire project to be completed on schedule. It is the longest path of planned activities to the end of the project, and it has the least amount of slack or float. So, if an obstacle or blocker occurs on the critical path, the project schedule will be directly impacted. Therefore, prioritizing these blockers would have been the most effective way to avoid further timeline deviations. References: Project Management Professional (PMP) Reference Materials, PMBOK Guide, Chapter 6: Schedule Management. Professional in Business Analysis Reference Materials, Chapter 4:
Elicitation and Collaboration.

According to the PMBOK Guide, 7th edition, section 4.3.2.1, when a project faces a technical issue that requires specialized knowledge or expertise, the project manager should consult with external subject matter experts (SMEs) and the team to find a solution. External SMEs are individuals or groups who have specialized knowledge or skills related to a specific aspect of the project, such as aerospace design. They can provide valuable insights, recommendations, and guidance to the project team. The project team consists of the project manager and the project staff who are responsible for performing the project work. They have the most knowledge and experience about the project and its deliverables. The project manager should involve both the external SMEs and the team in the discussion of the technical issue, as they can contribute different perspectives and ideas to resolve the issue. The project manager should also communicate the issue and the proposed solution to the project sponsor and other relevant stakeholders, but they do not need to be part of the initial meeting.
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PMBOK Guide, 7th edition, section 4.3.2.1
PMP Exam Content Outline, Domain II: Process, Task 5