Will there be a Photoshop, Affinity Photo, or stand-alone version of BlurXTerminator?

There are no plans to make a version of BlurXTerminator for Photoshop. Deconvolution is not just any sharpening algorithm: it has a precise mathematical definition. It requires linear image data with minimal processing for optimal results or indeed to even be called deconvolution. Linear image processing is difficult to achieve using Photoshop.

In addition, the vast majority of serious astrophotographers moved away from using general photography applications like Photoshop even before the introduction of BlurXTerminator. A small independent software developer like RC Astro must carefully choose where to invest its time in order to create, maintain, and support high quality tools where they are most needed.

This likewise applies to the possibility of a stand-alone version of BlurXTerminator.  A tremendous amount of infrastructure built into PixInsight, such as reading and writing myriad file types, performing various pre-processing steps, etc., would need to be re-implemented in a stand-alone app. This code would also need to be made completely cross-platform to support Windows, MacOS, and Linux. This heavy lifting is already done in PixInsight – quite elegantly in fact – and is leveraged heavily by BlurXTerminator. Reinventing these wheels is beyond the development resources available considering that the existing RC Astro tools must be maintained and continually improved, not to mention the need to devote time to completely new tools.