seems to work

dtoverlay/Makefile

@@ -12,14 +12,17 @@ all: $(DTBO)
 $(DTBO): $(DTS)
 	dtc -@ -I dts -O dtb -o $@ $<
 
-install: $(DTBO)
-	sudo cp $(DTBO) $(OVERLAY_DIR)/
-	@if ! grep -q "^dtoverlay=$(OVERLAY_NAME)$$" $(CONFIG_TXT); then \
-		echo "dtoverlay=$(OVERLAY_NAME)" | sudo tee -a $(CONFIG_TXT); \
-	else \
-		echo "Overlay already present in config.txt."; \
-	fi
-	@echo "Installation complete. Reboot your Raspberry Pi to activate the overlay."
+load: $(DTBO)
+	sudo dtoverlay -d . $(OVERLAY_NAME)
+	@echo "Overlay loaded"
+
+unload: $(DTBO)
+	sudo dtoverlay -R $(OVERLAY_NAME)
+	@echo "Overlay unloaded"
+
+list: 
+	sudo dtoverlay -l
+
 
 clean:
 	rm -f *.dtbo

dtoverlay/counter.dts

@@ -7,13 +7,12 @@
     fragment@0 {
         target = <&gpio>;
         __overlay__ {
-            gpio_led_blue: gpio_led_blue {
+            gpio_led_blue: gpio_led_blues@26 {
                 brcm,pins = <26>;
                 brcm,function = <1>; // output
                 brcm,pull = <0>;     // no pull
             };
-
-            gpio_led_red: gpio_led_red {
+            gpio_led_red: gpio_led_reds@21 {
                 brcm,pins = <21>;
                 brcm,function = <1>; // output
                 brcm,pull = <0>;     // no pull
@@ -22,3 +21,4 @@
     };
 };
 
+