Yes, just add https://mastodon.world/@LemmyWorld.rss in a rss reader of your choice.
Works with any mastodon account. I.e you only need to add .rss to any url.

Oh,forgot to mention there is support for sharing screen and separate window on desktop. Unsure about mobile clients.

If those you wish to have a video call with already have each others phone numbers then Signal is a option. It supports up to 40 participants. Available on Android, iPhone, Windows, Mac and Linux.

Signal has other great chat/messaging features too.
Also a unofficial community on Kbin