Plagarism is passing off others' ideas or words off as your own without attribution. IMO there is an argument to be made whether conjuring up text from a model

Plagarism is passing off others' ideas or words off as your own without attribution. IMO there is an argument to be made whether conjuring up text from a model of others' words should qualify as "others' ideas or words", but if it isn't technically academic plagarism I reckon it is a distinction without a difference. The concern with academic plagarism isn't primarily IP, so I reckon it doesn't inherently matter whether "others" being borrowed from is a particular author. Also, There's a commonly understood threshold for plagiarism where a single word won't qualify and a phrase probably won't qualify, but a whole paragraph does. That is why Grammarly isn't plagarism, not because it is software.