Have you tried using the Fluxbox implementation version MX Linux makes available? They have put tons of work into their Fluxbox implementation. Perhaps it will provide you with some useful ideas/ help. Their Forums are also quite responsive & helpful. FWIW . I am not a paid announcer ;) ...

I have no idea why this link did not appear... here is a retry on the material.

https://eirenicon.org/2023/12/13/xorg-wayland-transition-thoughts/

I, also, use systemd.... When running Wayland and x11 window managers there are quite a few dependencies on systemd that are easiest ti handle by just using it. ;)

Another factor impacting memory significantly is the kernel used. My liquorix kernel "updated" this morning and I am using 200MB less memory than yesterday; it must be my lucky day. 😜

Given your observation, I'm guessing you have not used i3wm very much. i3 is extremely flexible and powerful. But as with most Window Managers, i3wm is geared towards those who prefer to build a highly customized environment. If you haven't already, this is a good read. https://i3wm.org/

I wish I had a good answer/ solution.

Have you asked on the Arch, Endeavour, Manajaro Forums? Perhaps someone there has an answer. My observation is that Wayland, in general, is a bit wonky and unpredictable with certain x11 tools and their operation. This seems it may be one of those. If you are in need to something similar to Conky, you might try EWW. I have seen that tool behave unpredictably at times as well.... but it's 'supposed' to be Wayland friendly.

Are you running 1.19+ of conky? Have you installed conky-all?

I have no idea... I am one of those who refuse to use nVidia