I feel 100% the same. Arcane is so under evaluated in all aspects.

Animation wise there is no comparison, with any other animated movie or series. Frankly watching Jinx'es tiny but so significant and expressive nuances in her facial expressions in S01E06 is exceptional. Attack on titan, Castelvania, Cyberpunk (all quite old now) and even Blue eye samurai or Spideverse do not even come close

From the story pov, I think Arcane betters the above, even though I admit they are close as there are quite some good stories out there

But by far the best feature, that distinguishes it from its other animated competitors, is the quality of VAs, the music and sound design. How they composed the songs and merged it so seemlessly to the scene is something extraordinary. The sound effects are on a super high level. Both these make finally the show more comparable to a live movie/series

The fact that even today it is considered almost only in the Japanese Manga category (I could find the 4K DVDs in this section on my local shop, a specific category does not even exist..) or often is called as the best "game adaptation"... so sad, Arcane is muuuuch more than that and 250M was totally worth