I'd argue that mastodon gives you as an end user significantly better control over what you see than yarn does. You can mute by keyword, for instance--if you don't want to see posts about "ChatGPT" anymore, you mute that word and poof! those posts are gone. You can block individuals, or entire instances. You can mute hashtags. You can set timed mutes/blocks, for instance muting a person for 1 hour or 1 day and then having that mute or block automatically reversed. Once you learn how to use those tools, the chance you'll ever see a post you don't want to see is pretty low unless you're being actively harassed or you wade into the "federated timeline". I can't speak to the administrator tools since I've never set up an instance and played with them. Anyway, my mastodon accounts feels pretty slow to me, and I feel like I'm in full control of what I see--nothing at all like being shouted at.
yarn, as it is, seems ripe for abuse if there's ever a large influx of potentially malicious users, because it does not have fine-grained end-user tools like these. What would you, as an end user, do if someone stood up a yarn pod full of assholes who all collectively decided to twt at you all day every day? What would your options be to stop that flood, which would very much feel like being shouted at? At the administrator level, I had to drop the OS and block a range of IP addresses to keep spam users from continually registering on my pod, for instance; yarn only gave me the option to manually delete them one-by-one as they popped up.