Smart Chunk Loader is a data pack for optimizing chunk loading. Usually you start to lag a lot when chunks are generating, but this fixes that.

So what does Smart Chunk Loader do?
Well, to put it simply, this data pack optimizes chunk loading and unloading to improve Minecraft performance by loading only necessary chunks around players and unloading those that are no longer needed. It does this periodically, rather than every game tick, to reduce the performance impact.

As a more detailed description:
It periodically manages chunk loading and unloading to ensure that only necessary chunks are loaded around players, thus optimizing performance. It does this by using a timer system to reduce the frequency of these operations to every 5 seconds, rather than every game tick, to minimize performance impacts.

So what does this NOT do?
This does not increase the loading time of chunks, only increases FPS when doing so.
Another more detailed description:
The data pack does not directly increase chunk loading speed. Instead, it optimizes the overall performance by managing which chunks are loaded and unloaded, thereby potentially reducing the overall workload on the server or client. This can result in a more efficient use of resources and smoother gameplay experience, but it doesn't inherently make individual chunks load faster.
For faster chunk generation, try C2ME and Noisium.

FAQ:

How do I disable/enable?
The pack is enabled by default, but to turn it off you use the command /function smartchunkloader:disable.
If you want to turn it back on you use the command /function smartchunkloader:enable.

I am not noticing an FPS difference, why?
There are a few reasons. The first reason is because you haven't installed the pack correctly. The second reason is because it only sometimes increases FPS, when the chunks are generating. The third reason is because the performance impact may vary depending on your computer's specs.

FPS Example:

Generating chunks in vanilla Minecraft:

Slow, sluggish gameplay with lagspikes, and FPS fluctates wildly.

Generating chunks with the data pack:

Significantly faster FPS-side, with less lag spikes, higher framerates and the FPS doesn't fluctate as much.

I hope you enjoy!