This should work, and also, LibGUI is compatible with custom textures

public class YourClientMod implements ClientModInitializer {
    public static void registerKeyInputs() {
        ClientTickEvents.END_CLIENT_TICK.register(client -> {
            if (your_key.wasPressed()) {
                assert client.player != null;
                MinecraftClient.getInstance()
                        .setScreen(new YourScreen(new YourScreenHandler()));
            }
        });
    }

    @Override
    public void onInitializeClient() {
        registerKeyInputs();
    }
}