Hi @mediasync,
Yes, it is possible to set up adaptive bitrate using the Nginx RTMP module and ffmpeg.
See:
https://licson.net/post/setting-up-adaptive-streaming-with-nginx/
You simply need to add some additional configuration to /opt/kaltura/nginx/conf/nginx.conf.
In regards to using Wowza and the media-server and livedvr repos, this solution is not officially supported when using CE and so there are no official deb packages though as you can see, the repos are FOSS and licensed under AGPLv3 so if you’d like to deploy them manually from the source, you are welcome to do so.
Like I said, you’ll also need to pay for a Wowza license. If you do decide to try, use Wowza of version 4.7.1. It’s important to state that I cannot commit to providing support for this but you are always welcome to post additional questions.