There is a fractal pattern between authentic and inauthentic writing.

Crude tools (like Google docs revision history) can protect an honest student who engages in a typical editing process from false allegations, but it can also protect a dishonest student who fabricated the evidence, and fail to protect an honest student who didn't do any substantial editing.

More sophisticated tools can do a better job of untangling the fractal, but as with fractal shaped problems the layers of complexity keep going and there's no perfect solutions, just tools that help in some situations when used by competent users.

The higher Ed professors who really care about academic integrity are rare, but they are layering many technical and logistical solutions to fight back against the dishonest students.