recents still has animation even though animations are turned off on my phone

Thanks for the report! On Android the recents screen is provided by the system's built-in launcher, and third-party launchers like Niagara can't interact with it, see App Launch Animations. So the animation you see there most likely comes from your phone's system rather than from Niagara.

One thing that would help pin it down: does the recents animation also play, with animations turned off, when your stock launcher is set as default? Your form says that wasn't tested yet, and that comparison tells us exactly where to look.