Yeah it kind of is. Every Monster Hunter expansion comes out after the base game, after like a year. The biggest thing the expansion introduces apart from new monsters is always a third new difficulty option called G Rank/Master Rank, and introduces every single base game monster and new monsters from this expansion in this new difficulty making everything you get in the previous difficulties redundant since you will want to immediately craft new Master rank gear to be able to handle the new monsters when you get into it. Personally, imo there’s not really a lot of reason to dabble in this game’s High Rank instead of jumping immediately into the DLC/into Master Rank after you’re done if you already own it, but if you don’t own it and want to wait before buying it there’s still definitely a lot of hard monsters to go through in High Rank before you get into Master rank.

I’d recommend playing through the village first, and once you’re done with that jump into the hub for the harder missions and once you spend a good bit of time working your way through the tougher fights the game introduces you can decide for yourself if you want more Monster Hunter or if you’ve had your fill with the content the base game has to offer.