Snowmix
Video mixer for mixing live and recorded video and audio feeds
...Supported for Ubuntu, Mint, Debian, Alma, CentOS, EndeavourOS, Fedora, Mageia, Manjaro, MX Linux, OpenSUSE, RHEL, Rocky and macOS.
Free support in the discussion forum.
See Snowmix in action on Youtube http://www.youtube.com/user/Snowmix4video