a low latency kernel (whatever that means. I’ll get there to figure it out eventually)

It's a kernel with real-time process scheduling enabled by default.

In normal kernels a process can theoretically block all other processes from running for up to several seconds, which is obviously bad for time sensitive things like audio recordings or controlling a CNC-machine for example.

In real-time scheduling all processes are guaranteed time slices in more regular intervals. This is good for time sensitive things like audio recording, but since there is some scheduling overhead it's bad for single resource intensive processes or process trees like video games.

You can read more about the difference between a real time and low latency kernel here: https://help.ubuntu.com/community/UbuntuStudio/RealTimeKernel