Hi, I've both your nixies and numetron wemos kit, and I remake the code for fun... and to adapt it for DCF77.
I've seen that D4 is used for the optional PIR.But if so, D4 = GPIO2 is forced to stay at low level during startup, and then the ESP8266 should not (and in fact does not boot with my code), unless you disconnect the PIR during startup. Then you can reconnect, everything works fine.
I'm wondering how you workaround this fact, if it is not too much secret....