Friendly reminder that lemmy is still being actively developed. There will be many performance improvements in the future, as well as UI and whatnot. Stick around, create content and engage with your communities.
Lemmy.world is ran by a pro. Dude runs one of the most used mastodon instances. The fact that Programming.dev is stable while .world is not quite so, is purely due to the amount of users. Get 80k on this instance and you will see what happens..
I am eagerly waiting for usernames and for something to happen that makes people go to signal. The few people I had there ditched it when it lost sms support.
Others have already said, but I will reinterate:
You have to go to your account settings and enable "Show NSFW". It is off by default.