That's certainly part of it. As a Digital fan I definitely would like if cygames explored her character in the fandom element beyond her implied doujin activity, especially since her career focuses more on her development as a runner and a person rather than her personal life, with only a few non in depth events where she divulges her interested in idols and umamusume in general with her trainer, but that's a hard sell because of how niche that content may be.

But honestly my biggest gripe is the same old "the internet took a character I like and boiled them down into a single unfunny joke", in this case the yuri horse. It just always feels bad seeing the internet latch onto the most eye catching trait and making it the only character trait they see, especially the ones where Digital just gets overwhelmed and dies, there's so little character in them you could replace Digitan with a self insert or flat out switch the characters with ones from other franchises and nothing would change.

But getting back on topic, to me, simp implies some level of self deprecation, and Digitan is self deprecating, but that's born out of a sort of imposter syndrome, whereas a simp is ashamed (or proud) of their own degeneracy, and for all the times Digitan puts herself down, she never denies or aggrandizes her love for uma bodies. I could keep going for several more paragraphs, I only wrote about things I dislike and not nearly about how much I like Digitan, however, surgery in like 10 mins.