Stuff like this has been asked but after searching I can’t find anyone who has given a real answer to this niche use case.
I was thinking of making a custom interface in a game that allows you to
See the window of another external application
send input to it at runtime (I want to send custom macros to perform actions quicker than just using the original application’s tools alone as intended)
Sort of like virtual desktop but with very specific and custom controls for controlling a specific program.
Well, assuming you have control over the other application, you can implement any kind of IPC that you want, websockets, webservers, file system sockets, whatever. The specific purpose, though, doesn’t seem particularly well suited to Unreal, though…