At this point, the only way to implement blocking is to switch instances, it would seem. Or at least get an app, though that is the part that I know the least about. I switched instances myself specifically for this feature - and we've been saying how superb Discuss.Online is even, all the more notable for a smaller instance! - but I'm not sure how many others would think similarly. Still, they could be told that it's an option. Or perhaps !newtolemmy@lemmy.ca is almost dead at this point, with so few posts? Then again it's not the number that matters, if the content is relevant.