At this stage if you need to see stats about the call queue, you have to consider Power BI reports.
https://docs.microsoft.com/en-us/microsoftteams/aa-cq-cqd-historical-reportsThis information is not yet visible even for supervisors in voice enabled channels.
Activity report about agents, like how long they have been out, is even missing for some 3rd party Contact center solutions :) so I would not expect any report like this even in Teams natively at this stage. But it is lot required by supervisors even in our company.
Another option is third party solution for even more real time information about call queues and dashboards.
If agents are opt-in or out you can see only as owner of voice enabled channel. But you cannot force their status. Again that is more advanced feature available in 3rd party CC apps.
For realtime info about agents just recently MAF monitoring tool also announced real time call queue info.