In Android[0], the "back" button on the bottom is a triangle pointing left. The "home" button is a circle. The "show recent apps" button is a square. All are just flat shapes.
Completely unintuitive to anybody that's never used Android before.
Contrast that to the early days of Android where the Back button was a curved arrow, the Home button was an icon of a house, and the Menu button was the hamburger menu people are familiar with, except the lines were thinner.
[0] This may actually vary depending on what phone you have and if the maker changes these, but on my Pixel 6, this is the description.
Back symbol pointing left is probably less intuitive if your language isn't left to right oriented. Wonder if back symbols or back animations have ever been "localized" to orient based on the language used.
Android sort of gets a pass in that it's something that's constantly used by the user, so there's some ability to train people into arbitrary and unclear UXes, especially if they're only a few buttons (a good example is game controllers where what buttons do is completely disconnected from the letter or symbol they're assigned).
iOS is pretty similar in that a good number of the navigation gestures aren't super intuitive and not really discoverable until you build some muscle memory.
Completely unintuitive to anybody that's never used Android before.
Contrast that to the early days of Android where the Back button was a curved arrow, the Home button was an icon of a house, and the Menu button was the hamburger menu people are familiar with, except the lines were thinner.
[0] This may actually vary depending on what phone you have and if the maker changes these, but on my Pixel 6, this is the description.