The Maven repository given in the “Getting Started” page of the wiki (https://dl.cloudsmith.io/public/tslat/sbl/maven/) no longer exists. Has it moved elsewhere?

It exists just fine

You just can't browse to that URL directly because it's not a browseable maven at that location.
It works perfectly fine for the purposes of making a dependency

Alright, found out that it happened because SmartBrainLib-fabric-1.20.6:1.14.2 is missing from the maven (I have to use SmartBrainLib-fabric-1.20.5:1.14.2 instead).

🤔

I'll get new versions up on all the platforms soon, that's definitely an issue there