Sublinks will live alongside Lemmy, just like kbin does today. Some Lemmy instances might switch to it under the hood at some point, but as a user you probably woudn't even notice the change
To expand on this, some kbin instances have already similarly changed to mbin, and no one noticed.
Yeah, because I'm doing it more frequently. I think it's the design of this particular one. I've seen other comments say the same thing (on a video about how to clean it thoroughly, disassembling pump and everything).