i got that once, except it was my exact question with no response at all, then i noticed it was me that posted the question 4 years earlier.
i used to use stack overflow a lot back in 2007/08 but i cant remember the last time i actually got an answer.
It is my understanding that the only difference applies to hosted software. For example, Lemmy is AGPL. If it were GPL, then a company could take the source code, modify it and host their own version without open sourcing their modifications. AGPL extends to freedoms of GPL to users of hosted software as well.
A real example of this would be truth social which is modified Mastodon and as AGPL those modifications are required to be open source as well.