>>46819087I was gonna say Zoroark, but after thinking about it for a while, i think you're actually right.
Zoroark definitely started out as Gen V's intended shillmon, but holy shit they just completely dropped the poor thing right after after the movie. Also, for a shillmon, they clearly didn't think it through considering how lame it turned out to be in competitive. Add to that the fact that its actually awesome ability got completely cucked by the Team Preview feature added in the very same gen. Hell, it's pretty arguable that it even got cucked by Greninja in terms of being playable in Smash. Overall, Zoroark hasn't been "forced down our throats" in nearly a decade, and it's pretty forgotten by Gamefreak themselves, so i can't in good faith say that it's an overforced shillmon that nobody likes, especially since it's proven to be pretty popular as a hipster alternative to Lucario.
But Incineroar... in terms of a pokemon that had all the tools given to it in order for it to become popular and still managed to miss the mark, then he's most likely the biggest offender. Arguably the most used starter ever in Competitive, First Final Stage to be showcased, Masked Royal's main pokemon, alongside being actually playable in Smash. Despite all this, it was extremely divisive and unpopular for a starter. I believe anons mentioned he only had around 300 works in Pixiv after his first years and never broke Top 10 in Alola polls. I expected all the previously mentioned factors, especially Smash, would turn him into a Pokemon Star, but even though it did boost his popularity, it pretty much just made him more tolerated among the community instead of making it flat-out popular. Even shit like Inteleon turned out way more popular in one year than Incineroar did in 5 years despite being shit competitively, getting cucked by GF in everyway and having a pretty bad design. So yes, all things considered, Incineroar is the pokemon that best fits this description