This is the user manual for your model:
The switch is designed so that if it has not been connected to A z wave network, the LED is supposed to blink to tell you that. Yours isn’t blinking, so we know it thinks it belongs to some network, but probably your old network.
( or the switch is dead all together)
Since you can’t get it to blink by going through the exclude, it’s not hearing the exclude.
It’s probably a pretty old switch, and it may just have died, that does happen eventually. But the first thing would be to check all the wiring connectors and make sure they look good, including the one to the neutral since that’s the one that powers the radio. Just make sure nothing has come loose.