One of the main problems seems to be Feedly.
That doesn’t mean there weren’t other problems. But NetNewsWire, W3C Validator, and rssatom.de all seems fine now, if with major latencies.
I’m at the point where I can’t do anything else, I’ve tried everything. The problem will either go away or not.
Once again, thank you, Google, for killing RSS.
If you have something valuable to add or some interesting point to discuss, I’ll be looking forward to meeting you on Mastodon!