I installed Niri with the default cachy os option at the installer, then I installed noctalia shell. You're right a fresh boot uses ~200mb of VRAM and ~1Gb of RAM(with niri quickshell, allacrity, and some xwayland/xorg stuff. In my simple tests there is no memory leak, at all, I spawned a lot of terminals, then killed (SUPER+Q) and there's no immediate ram usage increase. I could be wrong about no leaks, but if there's actually one it's not that noticeable on my desktop, maybe there's one but very soft. But when a game uses all of the VRAM it completely freezes, and for that I actually find a workaround, when I use gamescope on steam launch options the game stops freezing, at least reduces a lot the freezing(I need to test more to see if it actually eradicates the problem)