Intro
I am personally a big fan of RSS, but I am not sure how the effort/reward trade-off would look like for Orion to do something useful and differentiated/enduring in this space.
I generally have seen 3 user views around RSS:
1) "I use RSS all the time, I use a third party or self-hosted RSS syncing service, and RSS is part of my regular workflow across multiple devices"
2) "I can see RSS being useful but am not sure how to do it right, I might dabble now and then"
3) "RSS, what's that?"
Frequent RSS Users
For regular and devoted RSS users (group 1), they will commonly have native apps. There are some fairly good free, open source, and paid options on Apple platforms, like Lire, NetNewsWire, Reeder 5, etc (to name a few, plenty more are available). These offer a range of sync options, including "server-side" platforms that use standard-ish APIs, or "app specific" approaches to syncing via iCloud/CloudKit.
I am not sure Orion wants to get into this space - there's plenty of apps already out there. Users are willing to pay, but there's many other apps that do iCloud-only sync, and can do the obvious things Orion would be able to offer. Likely Orion would be replicating a lot of what is already there, for minimal gain. Many RSS services are "subscription back-end" (or self-hosted/hostable), but on these ones, feed fetching is done via the server, and read (etc.) status is synced via the back-end.
There are also new options in this space emerging (Omnivore etc), that approach RSS from the other way around - Omnivore started out life as a "read it later" application, then added support for pulling in RSS feeds into their application.
Interested dabbling users
For these users, Orion might be able to offer something - they might like how Orion did RSS if it was differentiated or super easy to use. The question is if Orion can maintain these users, or if they will end up becoming "frequent users", and moving towards something more powerful quickly.
I started in this category, by playing around with TT-RSS and FreshRSS, before settling on Miniflux. I used various clients, including some on-device only ones, before settling on Reeder 5 and/or Lire, as they both sync to Miniflux. At least for me, while I did play around with many other apps, I ended up rapidly in that "frequent RSS user" camp, where there is a fairly high barrier to producing a useful RSS client app.
Non-RSS users
This is probably the biggest opportunity, especially if Orion doesn't frame itself as an "RSS app" per-se, but rather offers features they might find useful. Say a Kagi-style "daily briefing" or similar on their home screen, but based on the sources they are interested in.
Closing thoughts
I don't know if it makes sense to try to "be" a full RSS app. People who want full RSS readers likely have something, or have some specific "if it did X then I'd switch", but you would likely need quite good feature completeness. Looking at the Mac App Store, paid RSS apps support quite a range of sync/third party services.
Reeder 5 = Feedbin, Feedly, Feed Wrangler, FeedHQ, NewsBlur, The Old REader, Inoreader, BazQux Reader, FreshRSS
Unread = Feedbin, Feedly, Fever, Inoreader, NewsBlur
ReadKit = BazQux, Feedbin, Feedly, Feed Wrangler, Fever, FreshRSS, Inoreader, Miniflux, NewsBlur, The Old Reader, Tiny Tiny RSS
Fiery Feeds = Feedly, Feedbin, Fever, NewsBlur, Tiny Tiny RSS, Inoreader, Bazqux, FreshRSS, The Old Reader, Nextcloud News
Lire = Feedly, Feedbin, FeedHQ, The Old Reader, Inoreader, BazQux, Newsblur, Feed Wrangler, FreshRSS, Miniflux, Nextcloud News, Tiny Tiny RSS.
(Not on app store) NetNewsWire = Feedbin, Feedly, BazQux, Inoreader, NewsBlur, The Old Reader, FreshRSS
It strikes me that something powered by RSS, but not trying to be a "full" RSS app, might be a good starting point, rather than trying to build out all these integrations to attract in heavy RSS users.