Never seen an intuitive UI. Been on Linux since 2004, was working on company-provided Macbook and struggled with UI, was very happy to abandon it. I have Windows as a gaming OS, dual boot configuration with my Arch Linux, and let me tell you I game on Windows like twice a month, absurdity of this OS makes me not want to game.
For me the most intuitive UI is the one I built on Linux, with I3wm and a lot of custom scripts. This surely will not be intuitive for you.
Universally intuitive UI is a myth.
edit: UI designers, using right tools, definitely can and do make better UI, UI better suited for target audience, better working right out of the box. Keyword is “target audience”. One can’t say Windows UI is more intuitive, it’s UI a lot of people got used to. “Intuitive” has very different meaning AFAIK.
So Sync’s UI is good for you, you have used applications that make you kinda got used to Sync. It’s called anecdotal evidence I think, when you make conclusions based in single test case. I’m happy for you. I like Sync UI best of all too, I tried multiple Reddit clients and Sync was most convenient for me.