I don't have these providers, but this is the deal that I've seen many other people refer to in the sub. It's listed in the Usenet provider deals list: https://www.reddit.com/r/usenet/wiki/providerdeals ("Frugal Usenet w/ UsenetFarm + 300 GB Yearly Blocknews Account" -and- "Frugal Usenet w/ UsenetFarm + 750 GB Yearly Blocknews Upgrade").

If you look on the "Usenet Tree" link (https://svgshare.com/i/iG8.svg) it looks to me like FrugalUsenet falls under the Omicron company name (red highlighting), HW Media (Highwinds) backbone, and sold by the Newhosting provider (Frugal Usenet listed as the "resellers", or maybe, like you said, the reseller here is BlockNews and not Frugal under Omicron).

Usenet.Farm is the company name (green highlighting), "Its Hosted" backbone, Usenet.Farm provider, with multiple resellers listed, one of which is Frugal. I could be wrong, but I think the name of the reseller (showing up in multiple places) may be getting confused as being on the same backbone? The same reseller is selling access to more than just one provider / backbone, but either way, the unlimited annual data plan should be on a different backbone from the 300GB or 750GB block, not on the same backbone. At least that's what I've understood from many others.

so a better block account option would be Newsdemon on the UsenetExpress backbone

I don't doubt it could be a better backbone, but I don't see any kind of deal with Frugal for either of those, and a Frugal Usenet w/ UsenetFarm + block deal is what I've seen many people talk about on the sub as being a good deal and working really well for them. I prefer my Eweka connection, but I'm trying to provide another very popular option.

Additionally, as I mentioned, I have a 2TB block with the UsenetExpress backbone (from UsenetPrime). In my opinion, it's garbage. My SABnzbd stats show a 55% availability rate, which agrees with my memory of continually having problems completing files before I got Eweka.

EDIT: stats from SABnzbd

Probably about 55% of that 65.8GB of bw used was completely wasted on incomplete downloads, that had to be deleted and downloaded again once I got Eweka.