There are unified drivers of sort for the Epomaker NT68 keyboard, although still named after something else. You can download the latest installer here, named "GK6XPlus version 6.0.0.49" as this is written and previously an unofficial replacement for the original software hosted on GitHub. The official drivers for the GK6x keyboards were from Jikedingzhi, which has already has its mark on the plastic case of the keyboard. The installer downloads as a compressed folder of 60 MB, and installation requests around thrice as much storage space for the software. As seen above, installation is straightforward, although without some options, including for shortcuts and start menu items, and I have no complaints in terms of system utilization. As of now, GK6XPlus is the official software, so there clearly was a point where the first-party offering was dropped entirely.
GK6XPlus was originally written to be a command-line interface program, but has received a GUI over time. Javascript limitations have resulted in there being some limitations in GUI mode, such as the inability to change anything on the base layer of the keyboard, but it does make for a much easier means of customization for the average end user over typing something in CMD, of course. Knowing the source of the drivers explains why GK6XPlus looks and feels much more rooted in English than most from an Asian brand, although the provided resources, or lack thereof, are also evidenced by the poor user experience behind that polished look when they pushed it to support the AK84S as well. Some of this is also due to poor scaling with high DPI displays, with the software drivers stuck at a resolution of 1200x900. I ended up turning my 4K display down to 1080p to make the most of it.
Sadly nothing has changed from the last couple of times I have used it, so it still makes for a frustrating experience. Epomaker tells me they are working on improving the software—let's see when that happens. At this time, there is no detailed user manual specific to the NT68; however, the software user experience is identical to other supported Epomaker/Skyloong keyboards, so you may draw on any other manuals available on the Epomaker website. The first layer can't be re-programmed, but the other layers are fair play. The Driver 1 layer is for programmed functions that are too large to be saved onboard, which requires the driver to be running in the background. Key mapping is also not that hard with virtual keyboards and options to choose from, with blinking action items to save any changes. I still think that everything else might as well be thrown into the bin and created from scratch. While the many files and configurations over several updates ensure the many keyboards are supported, they definitely do add to the confusion. LE (presumably "Light Effect") files are available, but here too customization is a mirage unless you create your own, which is a line-by-line entry that is way more complicated than it has any right to be. Macros are a slight improvement, though the pre-recorded ones are questionable in their implementation and naming, with a recorder that is adequate. Here too it is an issue of older version remnants being the questionable base to which others are added to appear more up-to-date.