Don't have the time to do that myself just now, but a quick look suggests one month-related pattern: the first adventure in a year outsells later adventures in the year. (Which suggests an alternate possible explanation for anthologies selling better.)
I believe Monsters of the Multiverse was #8 and the core rules gift set was #9, but the rankings have shifted since (Mordenkainen's Tome of Foes moved up to the #8 slot, and several others moved around - though the top 7 are the same).
Worth noting that the "Dungeons & Dragons Game" category also includes third-party and non-game products (including Critical Role merchandise).
My hypothesis on the MTG setting is biased but I suspect that their purchases are more player focused. However there is less reliability that your DM would run them as many of them are very different for traditional setting and not as compatible to dungeon crawling and adventure as setting designed for it. They were designed to be Planeswalker playhouses. Especially later MTG settings.
MTG settings feel half baked. I have them all and I love their ideas but I find it so hard to use them in a campaign. There just isn’t enough guidance, it’s all very light flavor, light aesthetics, light narrative frames.
For example, Ravnica was, to me, a super inspiring book. But what I really needed from it was about one hundred small storyseeds that I could draw into an epic intrigue campaign. and tables for making flavorful Ravnica NPCs. And more then a single location for each guild.
I expect that since such tools are not included, not many DMs are able to easily use the book. So word of mouth doesn’t spread, and they don’t sell that well (still better then basically all other rpgs tho).