>>52562101Primarina was the least popular but the Alola starters are some of the most (if not THE most) equal among starter trio popularity, so much so that they swapped first place on polls multiple times throughout the gen.
The least popular in Gen 8 is straight up RIllaboom. Inteleon is polarizing, but that's a double edged sword-there is very noticeably a large subset of fans who like the design. Rillaboom not being controversial is it's biggest downfall-it's just considered fucking boring by most people and the only ones who think it's the best just like the other two less, which, surprise, isn't a formula for a genuinely liked Pokemon, especially when its competition end up growing genuine fanbases. The fact that it even got Top 30 for Galar on the POTY poll and didn't get shunted off to the shadow realms like Meganium, Emboar, and Chesnaught did is a miracle in and of itself