Yes, I realize that the "loading" was really just Javascript effects to present each element individually. I'm sure that artists and designers love that stuff. But the people interested in a programming language framework are people who have things to do and value their time - otherwise they would not be looking for a framework.
Sorry to sound so negative.
Website is still not optimised though. It's a big SPA that loads most things in advance and followed a pragmatic mindset. Better done than perfect. It's low priority to make that faster, however shouldn't be a problem though as the target audience usually has big bandwidth.
There's also common sense. There are 33 words on that page, and it took 5 seconds for them to appear. No amount of design can justify that.
Additionally, the work will be served better if https://deepkit.io/framework is the home page, not the nothingness that is the home page