The best way to influence the Domain Authority metric is to improve your site’s overall SEO health, with a particular focus on the quality and quantity of external links pointing to your site.
I had the same impression, but it also doesn't seem like apps group cross posts (at least sync doesn't) so if you don't wait between posts they end up next to each other in the all feed.
Well, various instances block each other, and mods and admins are not all on the same page. And just like it's important to have independent instances, it's important that single communities don't dominate either.
I think a better solution would be to make a github suggestion to visually merge crossposted threads.
Blocking is extremely rare, not the rule. It would have to be the norm for things to be necessary like you're suggesting. As it is right now for the vast, vast, vast majority of users you are spamming everyone and making Lemmy a worse place. I shouldn't have to block communities and entire instances to not be spammed.