The artist has always been the same (flower_poya). They just change their style over time. It’s actually quite difficult to have a consistent art style in general lol. I imagine it’s also harder for them to go from their usual single cover art to making quick comics that have deadlines. So their art isn’t as detailed compared to the cover/novel art they create.
No, idk how you came to that conclusion
I imagine the price point is also different, art like this is likely very expensive, but one panel is much cheaper than a cover. Since there are so many of them. They have little time to focus on details and aren’t paid enough to sacrifice their health to do so.
Did the artist change? I haven’t read it for a long time