There are only 3 real challenges to free speech at the tech level a) the need for CDNs at scale b) distortions of net neutrality c) nation-state firewalls.

All other claims are about social governance on private sites, where applying free speech doctrine is a stretch at best

Baseline free speech has expanded modestly since 1776 or whatever your reference point is.

About 20% beyond core case of government-critical speech in formally public spaces and media I'd say.

You can (for example) have more kinds of conversations in a bar without getting punched or kicked out by other patrons or management. You can teach more things in colleges than 100 years ago.

That's a genuine de facto increase in practical, informal free speech/expression.

But online free "speech" is, as @reneed has pointed out, not an expansion of free speech at all, but an expansion of reach. It is like the secondary freedom of the press to print as many copies as they can afford, not primary freedom to say what they want

If a newspaper wants to print more copies it has buy more printing equipment and front more upfront costs. Reach for a paper publication is not "free", but a function of desired circulation, which in turn is a function of demand prediction etc. But that logic is obscured online.