Oshino Shinobu has been a long time favorite.
Lately Blue Archive has had a lot of top quality lolis, it's hard to pic a favorite. The Game Dev club(Momoi, Aris, Midori, Yuzu(back)), Iroha, Hoshino. There's more, these are just ones off the top of my head.
This would explain the rare cases of posts having an entirely different comments.
I've used NGINX for load balancing and caching, but none of my projects have ever gotten this large. Dynamic content like Lemmy responses shouldn't be cached as data is unique for every user. Static content like imgs, vids, ext; would be improved by caching. I suggest caching the /pictrs/image/ route, should make large images load faster.
For caching Lemmy data, I'd suggest Redis, but idk if Lemmy currently supports it.
Even if Burggit becomes an island in the fediverse, I don't see that as an issue. I currently enjoy the community we have here, if I need to view discussions on another instance I can just make a different account there. It's not that different than having multiple rddit accounts for different topics. It's actually a bit easier as I don't have to log out of one to access another.