There has never been a situation where all had more equal access to speech than today. Printing presses were expensive and complicated machines, and distributing handbills was far slower and riskier than tweeting.
Today, anyone can make a website. If they say enough interesting things, they'll get eyeballs. Even if those things are false, and even if the algorithms of the walled gardens want to suppress them, they'll still get out.
I think perhaps you're underappreciating the difficulty of physical distribution. Having one's voice heard has always been the domain of the rich and powerful. Sure, platforms control promotion and discoverability today, but I doubt that gives them more strength to control dissenting views than was available in the days of the printing press.
It's a heck of a lot harder to effectively eradicate physical media than digital.
F.ex. if I shower a town with 250 physical leaflets + I post on all the major platforms, and immediately people of power attempt to suppress them, which do you think results in more people seeing them?
Well I think it depends on the situation. If you're trying to post something they have already built good defenses against (e.g. child porn, or maybe mocking the king of Thailand), you'd probably have better luck with the handbills, but then you'd also have a better chance of getting arrested. If you are posting something that isn't automatically suppressed, I bet social media would still get you more reach.
You're missing the third option however. Start your own blog, then just post links on all of the major social medias, and especially on some of the minor ones. Once your link hits the right Signal groups or Truth Social followers or whatever, it will fly around way faster than any samizdat ever could.
I agree with that - freedom of speech is one of the few things I think worth fighting for. We cannot fight for it while rejecting it.