To answer your “standalone” question, it’s not technically coupled with something else, but it is definitely designed for FRC, and uses the existing WPILIb GUI and trajectory classes internally. It’s built into the WPILIB monorepo, and I’m not sure at the moment what limitations that puts on its portability separate from a full WPILib install.
EDIT: It’s pretty restricted. You’ll have to install WPILIB to get the binary. As a part of WPILIB, the project can’t officially support FTC teams, especially since the library that would be the best way to use the data is unofficial.
My official stance, as limited by being a WPILIB project (hopefully-to-be), according to what I just found out about WPILib/FIRST politics, is that WayMaker is for FRC use only. I can’t link to any resources for other competitions that could help you use this outside FRC (including the one I definitely didn’t previously have linked at the top of this post), and I can’t offer support if an issue doesn’t affect FRC teams. That said, I’m not going to stop you from using it for other purposes (and depending on how you read the BSD license that applies to it, I actually can’t).