What you're describing sounds like the only way I can think of to use the UI to browse the photos. It's clunky, but I think since Pro is so centrally built around a spatial database system, all the non-spatial stuff has always felt kinda secondary to me, in terms of UX & functionality.
I suppose the broader answer, though, would depend on what your use case is, here. For example, we have photos attached to non-spatial tables in one of our field efforts, but that's because those tables are then related to spatial data. So I can view the photos from the top-level spatial feature and just navigate down the rabbit hole to see the photos.
If you're looking at attachments that have no connection to a spatial feature, then there's a fair argument for viewing them outside of Arc. Unless it was a live-updating service of some kind, I'd be tempted to periodically download the attachments and view them in my OS' native file system. As of Pro 3.3, there's now a built-in tool for extracting attachments, but even if I weren't still on 3.1, there's a strong chance I'd build my own tool in a case like this, so the file architecture maintains the hierarchy that I would've wanted from the table, initially.
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M Reed
"The pessimist may be right oftener than the optimist, but the optimist has more fun, and neither can stop the march of events anyhow." — Lazarus Long, in Time Enough for Love, by Robert A. Heinlein
