If it's the AxCrypt I think it is, it doesn't even run on Linux, never mind Raspberry PI or Milk-V for instance. And it's not free either. So it doesn't meet many of my requirements, unfortunately.
It still falls slightly outside of my zone of preference, though, as it's a .Net application, which limits which platforms it can be run on (I'm aiming for a tool that can readily be used on most of my devices, including on an old Raspberry Pi or a router).
Just for fun, I tested now to build and publish for an ARM processor running Linux (linux-arm) and the build worked fine. I don't have a device to test it on though.
So... as long as it runs Linux and has an ARM or ARM64 processor and sufficient storage & memory it could work! (It's not tiny like a pure C-program unfortunately).
Would be cool to try...!