Peeps, let’s dial back the hyperbolic rhetoric. Saying “no”- as a player or GM- isn’t tyranny.
I don't really want to debate the moderative merits of this point or clash with the Moderators here, that's not what this post is about.
It is about "saying no" in a game. It's not tyranny. If your DM has created a world with, say, no dwarves in it, just because "dwarf" is a race in the PHB doesn't mean you have to be allowed to play a dwarf.
I'm a fan of Mark Rosewater's lessons in game design, and Lesson #18 is: "Restrictions breed creativity." A DM that always says "no" to everything is of course problematic. But a DM that says "no" to certain things isn't stifling your creativity... the DM is simply redirecting it.
As an example, I like to have a conversation with my players during session zero about Counterspell. I point out to them that while it's great fun to Counterspell the BBEG's cool finisher, it's also a feels-bad for them to have their own super spell Countered... and that I believe what's sauce for the Goose is sauce for the Gander... I tell them I
recommend that we ban Counterspell and offer them several options (e.g., DC20's Spell Duel system or "Spellcraft check to recognize the spell being cast in order to Counter it" or "no counterspells at all"), so it's not a hard "no" - it's something we agree on - but there are other things I might say "no" to outright (e.g., if I'm DMing a Bronze Age game, I'm saying "no" to gunpowder ... and there isn't going to be a debate; if I'm DMing with someone I know was a victim of sexual assault, I'm going to say "no" to problematic sexual content... and there isn't going to be a debate - mostly to save that person from having to re-live it even in a debate).
If I tell you, "no, you can't do X but you can still do A through W" I don't think it's tyrannical... but if you refuse to try A through W because you want to X and nobody can tell you otherwise, perhaps YOU are the one being tyrannical. Tyranny isn't about "who says no to one thing (or a few things)" but will say yes to many (other) things. Tyranny is about "who will only say yes to one thing" and will say no to all other things.