In my experience, projects going to Wayland actually improves performance and system resource usage. I got around 200Mb RAM back, when I switched from Qtile X11 to Qtile Wayland. 900Mb on XOrg, 700Mb on Wayland. These are with the same configuration and the same programs being autostarted.
Wayland does improve performance but only in some perspectives (for example, UI smoothness). In my case the negative impact looked like CPU overhead. It was easier to make the system stutter and some apps like Firefox worked more sluggishly. I suspect it’s because of how Wayland works fundamentally.
EDIT: you know the society is doomed when it downvotes comments about personal experience.
CPU overhead
I highly doubt you can conjure up a Wayland compositor that consumes more than 1% of your CPU, even eye-candy nightmares like Hyprland will not have any significant CPU usage.
