How to install obs-ndi plugin and the latest version of obs studio
using the official ppa
The latest version of obs studio is 25.0.8 in the ppa repository,
the version of obs in the ubuntu repository is 25.0.3 which is too to install the obs-ndi plugin
So you need to uninstall obs studio from the ubuntu repository and install the latest version using the ppa, then you can install the obs-ndi plugin
obs studio linux ppa
https://obsproject.com/download
obs-ndi plugin
https://github.com/Palakis/obs-ndi
ndi tools
https://ndi.tv/tools/
reaper vst audio plugins for windows
https://www.reaper.fm/reaplugs/