I know cloudflare has a free tier and allows you to put rules like this in place. AFAIK you’d have to use them as DNS at least in order to use this feature. I use Cloudflare tunnels and access to facilitate remote access to my home-server, and I know I have this same rule in place.
Do people not use a VPN with Usenet at all? I have one for torrents to get my Linux ISOs but I just assumed I should also use one to get my news from Usenet.