No, they aren't. They are meant to be followed -- at least most of the time.
In our silat class, we learn rules of movement, based on what we consider efficient and useful principles or laws that govern the art. "Don't move two bases at once" -- except now and then for full evasion, wherein getting out of the way is more important than sticking to the usually-useful rule.
Breaking a rule because you don't know any better is not quite the same as breaking one because you are doing so for a specific purpose.
In Thong the Barbarian Meets the Cycle Sluts of Saturn, Reaves and I used as many said-bookisms and adverbs as we could shoehorn into our prose: We were making fun of three different pulp writers: Robert E. Howard, E.E. "Doc" Smith, and H.P. Lovecraft, all of whom leaned hard into that overblown style of writing. (Out-of-print, and last time I looked, Thong is a collector's item, going for about $250 for the basic hardback, Lord know how much one of the leatherbounds might go for these days.)
Observe these sentences, from Thong:
"'He insults us!' One-Eyed Dick ejaculated as he reached for his sword."
"'He does?' Bwuce asked questioningly."
"'The goddess Peristali did not grant me relief," he said constipatedly ..."
They stink -- but they are supposed to stink.
All three of the writers we were lampooning had a tendency to florid writing, Howard and Lovecraft more than Smith, and part of the point of the story was to sail the purple seas and try to harpoon as many gags as we could.
I know that em-dashes and ellipses have specific functions in prose, and more often than not, I will misuse them. I'll have sentences with an em-dash fore and aft. I can't remember the last time I used a four-dot ellipsis; I just don't like how it looks on the page ....
Strunk and White open their book on writing thus: "Form the possessive singular of nouns by adding 's."
No shilly-shallying around, but -- wait: "Exceptions are the possessives of ancient proper names ending in -es and -is, the possessive of Jesus' and such ... "
Now and again, a word ending in a double "ss" doesn't look right to me if I add an 's, so I won't do it that way. (The heiress's fortune? Naw. I like heiress' better.) But I know the rule, and if called on it, can offer a defense.)
Commas get tricky. Where to put them? Where I want to offer a pause in a sentence that's not as much as semi-colon or a colon or as sudden as a dash or as final as a period. I use the serial comma in lists of names; several publishers don't use it that way now, so the house style drops one from my lists: I'd say, "Bill, Larry, Bridget, and Tom;" Ace will take Bridget's comma away from her.
"Ain't my bidness," ticks off the spellchecker and some copy editors, but that spelling in dialog is what I want my old Texas Ranger to say, and not "business."
Your goal as a writer is to communicate as clearly (and cleanly) as you can, and is already limited because words are all you have to do it. Go read Mark Twain's Rules of Writing -- they are as valid now as they were when he wrote them. Particularly in this discussion #14 and #18.
But know that you can break these if you have to.
He said, know-it-all-ingly, and ending his sentence in a preposition.