The blog post you reference clearly describes a limited blocklist. As the submission says, no other mainstream browser has blocked all third-party cookies yet.
> Safari continues to pave the way for privacy on the web, this time as the first mainstream browser to fully block third-party cookies by default. As far as we know, only the Tor Browser has featured full third-party cookie blocking by default before Safari, but Brave just has a few exceptions left in its blocking so in practice they are in the same good place. We know Chrome wants this behavior too and they announced that they’ll be shipping it by 2022.
I really thought Firefox did all of this already too. I have no justification for not having truly checked. Hopefully other browsers from Safari will not be far behind.
I hope that there might be a way to safely auto-sync my Firefox profile, bookmarks and history especially, to Safari iff it's really the more secure of the available browsers for iOS.
I guess later is better than never, but this seems like something they could have done long ago.