'Green Recorder is a simple desktop recorder for Linux distributions. You can use it to record audio and video on almost every Linux interface. Released under GPL 3, it now also supports Wayland.

Green Recorder 3.0 supports avi, mkv, mp4 nut and gif. Wayland’s GNOME session supports only WebM. The user can choose the audio input source from a list as well as can set default values from the preference window.'

-- source: https://itsfoss.com/green-recorder-3/

Just tried it and it works! Previously, I had used recordMyDesktop (GTK UI), which only supported Ogg Video.

Cheers, Peter