Why are presets showing on Camera Raw, but only some on Camera Raw Filter on PS?

If a preset uses features that are available only in the full Camera Raw import converter, that preset might not show up in the Camera Raw filter in Photoshop.

For example, if a preset uses a raw profile such as Adobe Landscape, those are available only when converting a raw file on import through the Camera Raw import filter, not when applying Filter > Camera Raw to a layer in a Photoshop document. But a creative profile (e.g. LUT based) is available for both raw and non-raw files, in the Camera Raw import converter and in the Camera Raw filter.

The Camera Raw processor is very different from the Camera Raw filter.

A raw file from a camera cannot be opened directly into Photoshop. It has to be demosaiced and processed into an RGB file first, and this is what the ACR processor, the plugin, does.

Once the RGB file opens into Photoshop, a lot of processing has already been done, and many processing steps have already been performed. Most of those presets apply only to raw processing in ACR.

The ACR filter in Photoshop is a small subset of the ACR processing engine. The RGB file in Photoshop jumps in at a much later stage in the ACR pipeline.