Google's hosts are all allowed, and so is authentication with Google's IP allowed, in the "Allowed IP Addresses" settings.
Check blog post again. No need to allow hosts.
Freeradius, running on pfSense, can access freely all IPs on the Internet, as it is just an outbound connection over WAN.
Netgate's blog post is written with pfSense 2.6.0 (or 22.05 Plus - identical I guess) and it should work.