Tried to use the particle generator as its own block for generating particle. Placing block, right click and shift right click not working. Just a block with no function currently.
Using:

• Minecraft 1.16.5
• Forge 36.2.39
• Mod-Version 3.0.27.462-universal
• BrandonsCore Version 3.0.15.248-universal

All togehter with 111 other mods.

It's still a WIP.

But the Particle Generator worked in earlier versions. Why not in the 1.16.5? And will there be an upcoming version on 1.16.5 with a working Particle Generator?

Again, because it's a WIP. Just like the Celestial Manipulator isn't in the 1.16.5 version. Draconic Evolution 3 for 1.16.5 is in beta still, and not everything works. The particle generator is there strictly as a crafting ingredient for the Energy Core Stabilizers.