I was ranting exactly the same just yesterday. Nowadays UI designers seem to have forgotten all about affordances. Back in the day you had drop shadows below buttons to indicate that they could be pressed, big chunky scrollbars with two lines on the handle to indicate "grippiness" etc.
A few days ago I had trouble charging an electric rental car. When plugging it in, it kept saying "charging scheduled" on the dash, but I couldn't find out how to disable that and make it charge right away. The manual seemed to indicate it could only be done with an app (ugh, disgusting). Went back to the rental company, they made it charge and showed me a video of the screen where to do that. I asked "but how on earth do you get to that screen?". Turned out you could fucking swipe the tablet display to get to a different screen! There was absolutely no indication that this was possible, and the screen even implied that it was modal because there were icons at the bottom which changed the display of the screen.
So you had: zero affordances, modal design on a specific tab, and the different modes showed different tabs at the top, further leading me to believe that this was all there was.