No, deleting an inactive agent from the queue will not affect the metrics that Alex is monitoring in queue reports in Genesys Cloud CX Performance menu. A queue report is a report that shows various metrics and details related to queue performance and activities in Genesys Cloud CX. A queue report can help you measure and improve various aspects of your queue, such as:
Service level
Abandon rate
Average speed of answer
Average handle time
Interaction volume
Deleting an inactive agent from the queue will not affect the metrics that Alex is monitoring in queue reports because:
A queue report only counts interactions that spent time in the queue, but an agent-based report counts any interactions an agent worked with. This means that the totals in a queue report and an agent-based report may not match exactly, even if they include the same agents or queues. This is because a queue is a stand-alone entity from the perspective of Genesys Cloud CX reports, and queue metrics and agent metrics can differ for various reasons, such as:
An interaction spends time in multiple queues
An interaction abandons before an agent handles it
An agent is a member of more than one queue
An inactive agent is an agent who has not logged in to Genesys Cloud CX or has logged out. An inactive agent does not affect the metrics in queue reports because they do not contribute to various metrics and details related to queue performance and activities, such as:
Offered count
Answered count
Abandoned count
Transfer count

Explanation
The performance view for Agents is used to view real-time metrics, such as status, time in status, calls answered, average talk time, and average ACW in Genesys Cloud CX Performance menu. The performance view for Agents is a view that shows various metrics and details related to agent performance and activities in Genesys Cloud CX. The performance view for Agents can help you measure and improve various aspects of your agent performance and activities, such as:
* Availability
* Productivity
* Quality
* Conduct
* Satisfaction
The performance view for Agents is used to view real-time metrics, such as status, time in status, calls answered, average talk time, and average ACW because:
* Real-time metrics are metrics that show the current data for agents, queues, skills, interactions, and flows. Real-time metrics are updated every 10 minutes in Genesys Cloud CX Performance menu . You can see the current values of various metrics, such as service level %, abandon %, customers waiting, and active agents.
* Status is a metric that shows the current state of an agent in Genesys Cloud CX. Status can indicate whether an agent is available to handle interactions, busy with an interaction, or away from their workstation. Status can also indicate the reason why an agent is away or busy. You can see the current status of an agent in the performance view for Agents.
* Time in status is a metric that shows the amount of time (HH:MM:SS) that an agent has spent in their current status. Time in status can help you measure the availability and productivity of an agent. You can see the current time in status of an agent in the performance view for Agents.
* Calls answered is a metric that shows the number of calls that an agent has answered during a specified period of time. Calls answered can help you measure the productivity and quality of an agent. You can see the current calls answered by an agent in the performance view for Agents.
* Average talk time is a metric that shows the average amount of time (HH:MM:SS) that an agent has spent talking with customers during a specified period of time. Average talk time can help you measure the productivity and quality of an agent. You can see the current average talk time of an agent in the performance view for Agents.
* Average ACW is a metric that shows the average amount of time (HH:MM:SS) that an agent has spent performing after-call work (ACW) during a specified period of time. ACW is the work that an agent does after completing an interaction, such as updating records or sending emails. Average ACW can help you measure the productivity and quality of an agent. You can see the current average ACW of an agent in the performance view for Agents.
References: https://help.mypurecloud.com/articles/performance-dashboards-overview/
https://help.mypurecloud.com/articles/agents-performance-views-overview/
https://help.mypurecloud.com/articles/agent-status-overview/