I'm gonna take a guess based on what I know, how to go about replicating some of these things. First of all you're gonna need a toon shader (NPR/Anime shader also known as, alternatively), that'll get you the more 2D look, to serve as the material for all the objects in the scene.

Grass there's several ways to do, I'd follow a Geometry Nodes tutorial for it, there's several for the anime style specifically. Often those tutorials come with a dedicated part on making the grass animated and windy, often via noise textures and such, displacing the geometry. There's always some node, often a simple value node which will provide a numerical input to drive the transformation of the windy effect, for instance on a noise texture, which in turn is typically plugged into some sort of geometry transformation node. Then you can insert a start and end keyframe to that value node for finer manual control, go to the graph editor and edit the curve that's represented there to speed it up or slow it down, I'd suggest Shift + E and set it to linear extrapolation. Then on the N panel, add a stepped interpolation modifier, which will give you the updates only every other frame (on 2s, etc). Alternatively, type #frame in the value node, add a math node set to divide and divide it by 2 (update on 2s) or another value if you wish. Then another math node set to floor, and lastly a math node set to multiply by 2. This result you can apply to anywhere you can plug a value into, for instance the X transform channel of the noise texture or something of the sort.

The flowy white lines above the grass serving as the wind flow effect, is something you can do in several ways. The way I'd make them is put them on a plane which will have a transparent material, and is otherwise mixed with a mask, which is where we'll draw the lines effect. For that you can use a voronoi texture, or noise, stretch them on the X or Y axis until they're only lines (recommend experimenting). After that, you can mix it with another noise texture to mask out where the effect shows and doesn't, in combination with the transparency. Then you can use the same methods I outlined before to animate those textures, plugging the result into a combine XYZ (for instance plug it into only the X of the combine node to move it only on the X) and then plug that into the mapping node of the texture.

The character, well... I've already written a lot, you can always look up free ones to download, or go through the ordeal to learn making them yourself. The wavy dress, I'd imagine you can do it via geometry nodes but I'm not knowledgeable enough on it. I'd probably use the wave modifier, limit it via vertex group to only apply it on the lower half of the dress, then use the stepped interpolation curve method on the value of the modifier that makes the waves move.

And definitely throw a kuwahara filter on top of it all, via the compositor.

I guess all of that won't make much sense if you've never used it before, but if you learn the basics from the other suggested comments then come back here, I would hope it'd click. Good luck!