Hmmm. Been trying to find a definition of "atonal". Surprisingly, have drawn something of a blank. Even Schoenberg didn't like or accept the term.
it is a big vauge almost useless word. i try to think of it as 'alternate tonality' or maybe even modified polytonality perhaps (i.e. it is not so much 'atonal' i.e without tone? see how silly that is?, but rather, in many cases such as with serialism, it is that all tones are elevated in their importance, the center-tonal center we like to call it right?-is a moving target, each one is critical and just as important no matter how short it is in time or with how many other tones it comes in on, i.e tonal clusters, the sound combinatino of them as a whole then becomes an important resonant center,).
as for Scriabin foray into alternate tonality, i.e building on his 'mystic chord', etc. i think it can help to remember how there is also lots of symbolism in his music, i think sometimes we lose the meaning of his message if we fail to associate an alternate meaning to the sound, it is hardly ever sound for the sake of sound.
this is a nice summary of it for folks not super familiar with it, and it talks about his colored keyboard (he associated certain colors with certain keys and i think this began to lay the foundation for that modified organ that would display colors instead of make sounds....
https://www.lumiatra.com/Scriabin.html)
*off i go, up up and away!.....