You cannot. You never could. The difference that the Fediverse makes is that you can make your own instance.
In fact, in many ways Lemmy is even more authoritarian than Reddit, this is basically a Reddit 2.0. Here there is a modlog, but no modmail, no notification of a moderation action, no ability to ask questions as to why (if only so that you can avoid doing so again?), especially when the modlog merely says that the action was done by a "mod" (so even if there were a moderator chat somewhere, usually on Discord or Matrix since they don't bother discussing on Lemmy itself, or you wanted to send a DM, who would you send it to, unless you send it to literally all, thereby risking getting yourself getting banned from the entire instance for legitimately spamming DMs, bc no other means are provided to you!?).
Edit; I've been waiting since the Rexodus nearly two years ago for any of this to be fixed. Do you want to know what all has happened during that time? I'll warn you: it's actually worse than nothing, and instead it has actively taken steps backwards. Previously the mod account name was reported in the modlog, so you could DM the one who took the action against your content, whereas now that information has been hidden from you. This is the opposite of "transparency", a hallmark of democratic features of governance.
On lemmy.ml, people routinely get instance-wide banned from communities that they've literally never even so much as heard of!? More importantly, for a rule that is never written down anywhere or explained to new users - don't ever criticize the authoritarian regimes of Russia, China, or North Korea (perhaps soon the USA will be added to that list). On midwest.social numerous people have been banned merely for downvoting posts or comments offered by the instance admin, or for submitting reports (not spamming, just one) literally calling out cries for (not against) murder - ideological purity testing is real there. Meanwhile back on lemmy.ml, I can point you (if interested) to an actual conversation where a moderator tells a user that he wants to kill him - but ofc he is protected by the instance admins so nothing will ever be done about such occurrences, which for that mod I believe are somewhat well-known.
Now you understand, the "freedom" that the Fediverse offers is not extended to the users, but rather to the instance owners - i.e. the landlords rather than renters. If you want that freedom, you have to start your own server.
Or join one that offers it downwards to its users. PieFed offers MANY features facilitating democratization of moderation. Discuss.Online, a Lemmy instance, is quite well-known for allowing freedom to its userbase (though being located in the USA... for how much longer?). There are others - these are just ones that I definitely know about and recommend.
TLDR: you cannot and never could, that's a misunderstanding of the concept of the Fediverse, though there is potential to make freedom happen here, unlike Reddit where it's a lost cause from the start.