You can use exported equalizer presets from squig.link to be your global eq in Linux if you use Pipewire. First, place the txt files from squig.link into a directory of your choice. Then, for each eq preset, create a file $HOME/.config/pipewire/pipewire.conf.d/<preset_name>.conf with the following content:

context.modules = [
{
name = libpipewire-module-filter-chain
args = {
node.description = "<preset_name>"
media.name = "<preset_name>"
filter.graph = {
nodes = [
{
type = builtin
name = eq
label = param_eq
config = {
filename = "/path/to/<preset_name>.txt"
}
}
]
}
audio.channels = 2
audio.position = [ FL FR ]
capture.props = {
node.name = "effect_input.<preset_name>"
media.class = Audio/Sink
}
playback.props = {
node.name = "effect_output.<preset_name>"
node.passive = true
}
}
}
]


Restart Pipewire, and now you have a new output device for each eq preset. I have written some shell scripts that automate this task.