Turns out you can just save control bindings as regular project settings under input/. Who knew?

project.godot

@@ -21,7 +21,6 @@ run/max_fps=60
 
 ClubCatalog="*res://src/equipment/clubs/club_catalog.tscn"
 GameSettings="*res://src/game/game_settings.gd"
-BindingLoader="*res://src/game/binding_loader.gd"
 
 [debug]
 

src/game/binding_loader.gd

@@ -1,35 +0,0 @@
-class_name BindingLoaderType extends Node
-## Handles persisting action input bindings.
-
-const BINDINGS_FILE := "user://bindings.tres"
-
-
-func _ready() -> void:
-	# Map may not be defined if no keybinds have been written
-	if FileAccess.file_exists(BINDINGS_FILE):
-		print_debug("Reading keybinds from ", BINDINGS_FILE)
-		var map: BindingMap = load(BINDINGS_FILE) as BindingMap
-
-		# Overwrite InputMap with loaded bindings
-		for action: StringName in map.bindings.keys():
-			# Clear existing bindings
-			InputMap.action_erase_events(action)
-			# Apply loaded binding
-			var event: InputEvent = map.bindings[action]
-			if event:
-				InputMap.action_add_event(action, event)
-
-
-func write() -> void:
-	# Build map from input actions
-	var map: BindingMap = BindingMap.new()
-	for action: StringName in InputMap.get_actions():
-		var events := InputMap.action_get_events(action)
-		if events:
-			map.bindings[action] = events[0]
-		else:
-			map.bindings[action] = null
-
-	# Write to disk
-	print_debug("Writing keybinds to ", BINDINGS_FILE)
-	ResourceSaver.save(map, BINDINGS_FILE)

src/ui/menus/settings_menu/control_binding/control_binding.gd

@@ -19,6 +19,10 @@ var listening: bool = false:
 @onready var button: Button = %Button
 
 
+func _get_settings_key() -> String:
+	return "input/%s" % key
+
+
 func _ready() -> void:
 	# gdlint:ignore = private-method-call
 	super._ready()
@@ -99,6 +103,12 @@ func rebind(event: InputEvent) -> void:
 	listening = false
 
 
+func apply() -> void:
+	var setting: Dictionary = ProjectSettings.get_setting(_get_settings_key())
+	setting["events"] = InputMap.action_get_events(key)
+	ProjectSettings.set_setting(_get_settings_key(), setting)
+
+
 static func create(_key: StringName) -> ControlBinding:
 	var instance: ControlBinding = SCENE.instantiate()
 	instance.key = _key

src/ui/menus/settings_menu/control_binding/control_binding.tscn

@@ -2,7 +2,7 @@
 
 [ext_resource type="Script" path="res://src/ui/menus/settings_menu/control_binding/control_binding.gd" id="1_7mwhu"]
 
-[node name="ControlBinding" type="PanelContainer"]
+[node name="ControlBinding" type="PanelContainer" groups=["ControlBindings"]]
 theme_type_variation = &"CheckerContainerOdd"
 script = ExtResource("1_7mwhu")
 

src/ui/menus/settings_menu/settings_menu.gd

@@ -3,6 +3,7 @@ extends MarginContainer
 
 const SETTINGS_GROUP := "Settings"
 const VOLUME_GROUP := "VolumeSliders"
+const BINDINGS_GROUP := "ControlBindings"
 
 @onready var bus_mixer_list: HBoxContainer = %BusMixerList
 @onready var control_binding_list: VBoxContainer = %ControlBindingList
@@ -25,6 +26,12 @@ func _get_volume_sliders() -> Array[VolumeSlider]:
 	return elements
 
 
+func _get_control_bindings() -> Array[ControlBinding]:
+	var elements: Array[ControlBinding] = []
+	elements.assign(get_tree().get_nodes_in_group(BINDINGS_GROUP))
+	return elements
+
+
 func populate_control_bindings() -> void:
 	for action: StringName in InputMap.get_actions():
 		if not action.begins_with("ui_"):
@@ -47,12 +54,13 @@ func apply() -> void:
 		setting.apply()
 	for mixer: VolumeSlider in _get_volume_sliders():
 		mixer.apply()
+	for binding: ControlBinding in _get_control_bindings():
+		binding.apply()
 
 
 ## Write all applied settings to disk.
 func save_settings() -> void:
 	Game.settings.write()
-	BindingLoader.write()
 
 
 ## Apply settings and close menu.

src/util/binding_map.gd

@@ -1,4 +0,0 @@
-class_name BindingMap extends Resource
-## Serializable action input map. Used by `BindingLoader`.
-
-@export var bindings: Dictionary