One of the things I’ve found in researching writing online is that there’s lots of people who want to convince you that there are certain fixed and immutable rules for writing, as if writing was engineering with unchanging physical laws.
The problem with that approach is that while engineering is a hard science, writing is far more art than science. So maybe you break the rule about using words other than “said” for dialogue. If you tell a good story, do you really think anyone will really notice? And if your story is lacking, are any negative reviews going to include “he used lots of different words in place of ‘said'”? Somehow, I don’t think so.
Of course, you should always use proper grammar and punctuation, but even those rules aren’t unbreakable. Sometimes they can be broken for a marvelous effect… but they can also be broken to deleterious effect, so you want to be sure you intended to break those rules.
To me, there is only one fixed and immutable rule for writing: write the best story you can, using the best English you can. The rest will take care of itself, or be taken care of by your editor.
Don’t let the rules-happy people interfere with your writing.