Sadly Vizzdom doesn't support Sequoia at the moment, and recommends Element as an alternative for those on the latest macOS.
I used to just use AU Lab, but when I replaced my M1 Mac Mini with an M4 Mac Mini, I started to have problems: after a few minutes the audio would start distorting. I originally had the same problem on the M1 but I have no idea how I resolved it. I'm currently trying out Hosting AU (see the first post of this thread) to host AUNBandEQ and that seems to be working alright. CPU usage seems to be pretty low, despite it not being compiled for Apple Silicon.
Hosting AU combined with Blackhole seems to be a good solution, and gives you proper system-wide parametric EQ for free.
Also worth noting is that AU Lab was "always on" and consuming CPU whether there was any audio output or not. Hosting AU is only active when audio is playing and CPU usage drops off when paused.
I haven't tried Element, in part because it's a .pkg that requires installing, whereas Hosting AU is just a regular application. Probably the reason Element needs installing is because it seems to have its own driver that performs the function of Blackhole. I tried Element to solve other issues (detailed below) but it consumes CPU even when nothing is playing.
I have both my Mac Mini and my work laptop connected to my Sabaj A30a through a USB switch. Whilst AU Lab handled this gracefully, Hosting AU and Element don't. Workaround: create a multi-output device that routes to the USB device, set the output of Hosting AU or Element to that.
Additionally, Hosting AU doesn't remember its last configuration on startup. Workaround: in System Settings > Login Items, add the .hosting configuration file. It'll start up with the correct configuration.
tl;dr: it is possible to get proper EQ working on a Mac at no cost, with seamless support for disconnecting and reconnecting USB devices, and near-zero CPU usage at idle.