It’s already blank (
_:_:_:_:_:_).
For totally disabling MAC Address Randomization, I have done the following, since I encountered a similar issue (very low reconnection on resume)
Made the config file /etc/NetworkManager/conf.d/90-disable-randomization.conf
With the following content:
[device-mac-randomization]
wifi.scan-rand-mac-address=no
[connection-mac-randomization]
## FOR ETHERNET, OPTIONAL IF YOU USE ONLY WLAN
#ethernet.cloned-mac-address=permanent
wifi.cloned-mac-address=permanent
Then restart NetworkManager.service:
systemctl restart NetworkManager.service