In short, no they're not necessary. As others have already said, I think how a prologue is done and the purpose it serves is important in determining if you need one or not.
The type that I absolutely do not like and think almost every story would be as good without (or better, even) are types that just throw like... pure unedited world building in the reader's face. If you're just including a prologue to tell us about something that happened millions of years ago and has no direct tie to where the story actually starts... skip it, I say. Sure that conflict or world building lore may be directly relevant to where the plot is going, but that doesn't mean you need to lead with it. Often that sort of information can be woven into the story later on closer to when it becomes relevant, and after we've already connected with the character and their actual current day situation. Same goes for random blurbs of information. "this world is magical, and it works like this!" is just not a very effective way to convey that information, especially if that's the first thing you throw at a reader. Often there are more nuanced and enjoyable ways to show that early on than blatant explanations (this is something I partially sinned in in my first comic lol. I waited for a few pages before info dumping how magic worked but it was still not great. At least I contained it to a single page tho
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The type of prologue that I do like are those that are somehow separated from the main narrative, but directly do something to set up said narrative. Whether it be something that happened to the main character in the past that they don't remember well, or maybe we see some random characters discovering the mcguffin that our protagonist will later come into contact with early in the story, or maybe we see something from an unusual Point of View that's important to getting the ball rolling, or what have you. Basically so long as the prologue feels like its own actual mini chapter of sorts, y'know? It should still have stuff actually happening in the present that the prologue takes place in, and still be interesting enough to hook the reader, and all that.