As a parent whose student has worked with multiple essay entry editors/forms, they're almost all terrible with most students having to revert to writing the essay outside the system or risk losing their work multiple times. And this was with a simple editor - not more complex connections to even more sophisticated systems.
The budget available for educational technology is not sufficient to maintain the operation of the software, let alone sufficient to pay technical staff adequate to assess and select reliable systems.
Yeah, then you get a bunch of non-cheating students who are intelligent and just annoyed with the text editor will use cheating tools to insert their essay they wrote in a proper word processor - further poisoning the dataset.
The budget available for educational technology is not sufficient to maintain the operation of the software, let alone sufficient to pay technical staff adequate to assess and select reliable systems.