There are projects that provide access to text-only groups. See for example http://www.eternal-september.org/
I took a walk around Usenet a few months ago after I discovered that my ISP (Teksavvy, Canada) offers access, and I must tell you… it’s ugly. The groups I checked are either entirely abandoned or there’s a post every two months, and they’re overridden with spam.
I think you’ve commented this in the past, but: is there any chance that Fedia would get migrated to Lemmy? I understand you wanted to have Lemmy running (don’t remember the host now) as well as Kbin so that people could choose, but perhaps if Kbin is too beta, it might not be worth it.
That said, I appreciate immensely the work you’re doing here, so whatever decision you take is more than fine.