Korg always seem to have been a bit pragmatic with using ready-made hardware where other manufacturers go at great lengths to come up with their own solution.
They should really be working on their own solutions as they can afford it rather than buying from pool of hardware small businesses are struggling to secure.
Korg themselves now struggle delivering those synthesizers. In many shops they are sold out for months. They are in exactly the same situation as those small businesses. It's quite disingenuous to blame Korg for a shortage of parts that had no shortage when they designed and first sold those synthesizers (more than two years ago).
Also, even big brand names in the synthesizer world are often comparatively small businesses themselves. Korg is probably a lot smaller than you imagine right now. Their name is much bigger than the actual company.
Look at the inside of this Korg M3: https://www.personal-view.com/talks/uploads/FileUpload/37/98...
It seems like the operating system comes on an SD card (makes upgrades easy, I guess), and the power supply looks like a standard laptop power supply.