Thank you! Your post gave me the clue that allowed me to find the Feeds UI on Vivaldi. Nowhere else had I seen an instruction to start the Mail application first, and then search for Feeds there. Mail, Calendar, and Feeds are always treated as if they are three different features, and I'd always been trying to access Feeds as such.
Incidentally, I found out why I could never access Feeds. It turns out that Mail is accessible in only one instance of Vivaldi at a time, and I typically have at least two, and sometimes three, open at one time in separate workspaces. It's how I arrange my workflow, as Vivaldi is the only browser I use.
I agree with you that feeds need to be displayed in separate folders, I have 7 feeds defined, and although message names are prefaced by the account they're from, the messages are interspersed in a single list. That makes sense now, because when I tried out the Mail feature, I added two of my accounts, and those messages were likewise not separated as to the account they came from.
If this is just a beta issue, I'm sure it will be fixed. If, however, it's by design, then I see little hope that many will adopt Vivaldi (which I love, otherwise) as their feed reader. Or as their mail reader, unless they have a single email account (and want all of their messages dumped into a single folder).
I'm betting on the former, and I'm pretty sure, based on the quality of Vivaldi as a browser, that this issue will be solved while it's still in beta.
