Imo blocked users get less engagement, therefore it helps to some degree. Also, unlike reddit, it’s somewhat difficult to browse the Fediverse without being logged in. I’d guess that if any problematic content does slip through, it reaches a much smaller audience than if it were to slip through on reddit just because of how things are decentralized here.
edit: I tried it again and I now agree that it is easier to browse with an account. I saw a lot more content than the first time I tried it ~2 months ago