Should I open the ticket on the Soapbox repo or the Rebased one (assuming the backend here is Rebased) though?
The issue may not be with soapbox/rebased but with your rss reader. I just loaded my rss feed into nextcloud news and it loaded up. (It could be in part due to the really long titles) I'll try a couple other rss readers.

I tested with rss.app, rssguard, quiterss, nextcloud news, feeder, Read You, spaRSS DecSync, and Nunti.
Only Read You showed the same error message, but some of the feeders were better with the feed than others for sure. RSS guard portable failed entirely on a "protocol error" whatever that means.
Only Read You showed the same error message, but some of the feeders were better with the feed than others for sure. RSS guard portable failed entirely on a "protocol error" whatever that means.
- replies
- 0
- announces
- 0
- likes
- 0