Earlier quoted context omitted.
I think I would try to impose some structure and possibly have an actual moderator. I basically moderate an in person meeting once a month (though my title is chair, not moderator ). I'm supposed to keep things on topic, curtail problematic behavior and try to get us out of there on time. I also take written notes. How you do that depends on a variety of factors, including the personalities involved. So I would think…
This is great. We have written agendas but they're usually, "we will be discussing these three documents in this order" not an itemized list of concerns. The itemized list is dynamic depending on what comes up in the conversation. Do you try to solicit more granularity from participants beforehand to build into the agenda, or how does that work?
We typically go through the agenda and then talk a bit more generally afterwards. As long as it doesn't go too far afield or get too contentious, I'm tolerant of meandering topics for the last part of the meeting.
If it gets contentious and it's not really germaine, I try to say something like "This is getting really deep in the weeds about a thing we have no control over." and redirect conversation back to pertinent topics.