Camera Raw Filter greyed out on gigapixel. Max image size?

Hi community,

I composed a 51 photos panorama in PTGui. Started in LRClassic, exported the files as 16-bit TIFF to PTGui. In PTGui, saved my panorama (approx. 75 000px x 20 000px) as a 16 bit .psb (9.28GB)

Photoshop 22.3.0 : mode is RGB and Camera Raw Filter is greyed out and I didn't find any help here to get it working.

Idem when using the raw files directly in PTGui (not as TIFF) and saving as .psb

Is there some max image size or so to use camera raw filter?

Graphics : AMD Radeon Vega Pro II, "Prefer Adobe Camera Raw for Supported Raw Files" is on.

Thanks!