How to turn off connectivity in NetworkManager Arch Linux

I have a router I use for cybersecurity testing. It has no WAN cable connected — that's intentional and required for the setup. NetworkManager seems to block me from connecting to that network because it can't reach http://www.archlinux.org/check_network_status.txt.

Version: NetworkManager 1.56.1-1.

I've tried disabling the connectivity check the usual ways:

1. /etc/NetworkManager/NetworkManager.conf:

   [connectivity]
   interval=0
   

2. /etc/NetworkManager/conf.d/20-connectivity.conf:

   [connectivity]
   enabled=false
   

3. Both, with an explicit URI:

   [connectivity]
   uri=http://www.archlinux.org/check_network_status.txt
   interval=0
   

After each change I ran systemctl restart NetworkManager,but nmcli general still reports CONNECTIVITY: full, and it doesn't even drop to limited when I disconnect from the internet.

I also checked /usr/lib/NetworkManager/conf.d/ for default drop-ins, but I can't tell whether they override my etc/ config.

How do I actually disable this check on 1.56.1-1 so I can connect to a WAN-less LAN? What am I missing?