The later part of Scriabin's works gets into the realm of atonal music,
I know what you mean about the results of his stylistic development, but "atonal" really doesn't come into it; even that so-called "mystic chord" (based on part of the harmonic series) that permeates so much of his later music is tonally based, although the possibilities it opened up are more suggestive of quartal harmony than of triadic harmony.
I wouldn't suggest anything from Op. 56 onward for that reason,
There's no clear-cut border, of course, but this is perhaps about as useful a place as any if one is going to create one.
The technical difficulties go without saying. Check out his Op. 11 preludes for a good place to start. These are from Scriabin's early period and show influence of Chopin and possibly Rachmaninoff.
And fine they are, too although, to be fair, I don't think that Rakhmaninov had achieved enough to exert influence on anyone by the time Skryabin wrote them!
His early waltzes and mazurkas would do nicely as well.
Indeed, if something not too technically demanding is sought as a way into his music. That said, the Op. 74 Five Preludes - his very last completed work - are not of fearsome difficulty and why in any case worry about the reactions of others to a harmonic language with which they appear to be unfamiliar?
Best,
Alistair
Topic: Scriabin progression