This is a problem with the pixelization there is that there isnt enough geometry for the displacement to work properly. You could fix this by either subdividing the plane some more or adding a subdivision surface modifier.
I was caught in a bit of a Catch 22 with this one. Either:
Have a bright crown, but be able to see it,
Lower the emission but have the crown blend in with the background,
or Remove the volume and lose the nice shine at the edge of the image.
tbh I think the Glow and Light in the Crown is really nice.
Like its Bombastic basically Lava and the Glow makes it seem more Bombastic.
The Lava on the Terrain could use a little more work tho.
but overall its really nice.
I noticed the terrain emission didn’t work as intended as the volume makes it appear much more dull. Turning it up, however, made the whole scene a bit too bright.
As for subdivisions I did that more for the sake of my PC. Didn’t want any explosions today.