I've worked remote since 2014. In that time I've used Skype, Hangouts, Zoom, and Teams. Hangouts was the easiest to use, but also had more technical issues. Zoom has worked well and aside from privacy issues is my top pick.
In my line of work two people can get most things done in 30 min.
Four people, if you can stay on topic, 30 min. Realistically 45 - 60 min, depending on how chatty the group is.
Thankfully Slack can help cut down on meetings, if you create dedicated channels by project or topic.