Hi Jgjot,
You couldn’t have come at a better time! Yesterday JUCE6 got anounced, which will feature full VST3 support on linux! It is not available right away, but will be in june. A technical preview will be released beforehand, so you’ll be able to use that as well.
In the meantime, you can still build VST2 plugins for prototyping and switch to VST3 when it’s ready!