Since iZotope Ozone 5 is a legacy software product originally released over a decade ago, it is no longer available for purchase or direct download from the official iZotope website. However, many producers still seek it out for its specific "vintage" sound and lower CPU usage compared to newer versions.
VST3 Support: Ozone 5 explicitly supports the VST3 format, along with VST2, RTAS, and AU. vst plugin izotope ozone 5 vst3 link
The performance of Ozone 5 is excellent. The plugin is highly optimized and doesn't introduce any noticeable latency or CPU overhead. This makes it perfect for use in live performance situations, as well as in the studio. Since iZotope Ozone 5 is a legacy software
So, you have the installer, but your DAW only scans for VST3 (looking at you, Cubase 13 or Studio One 6). Ozone 5 won't show up. Use Ozone 11 Elements (free often) — vastly
If you never bought Ozone 5, you cannot legally get the VST3 link. iZotope does not offer Ozone 5 as freeware. However, there is a workaround for owners of modern Ozone.