Well, on modern Android phones you can connect a keyboard and a mouse not to mention often a big screen.
Making a smartphone that does not behave as a general purpose computer is stuping and not to mention dangerous (as the manufacturer can always use it as a general purpose computer for its own nefarious means).
> as the manufacturer can always use it as a general purpose computer for its own nefarious means
This is assuming the device is, in fact, a general purpose computer. This is true now basically all of the time, but it doesn't have to be.
I can imagine as a thought experiment an ASIC or FPGA based phone that implements a very high level application processor, while what we normally call firmware, OS and libraries are implemented in "pure hardware".
(I agree with your sentiment, but somewhat disagree with your apparent conclusion android phones are any better if you're worried about bad actors -- the baseband and DSP from Qualcomm are processors running code we can never touch underlying the entire hardware. Similarly, almost all other computer hardware have separate CPUs inside the main CPU where the mfc. runs their own secret code which cannot be tampered with or even directly seen sometimes)
Oh, no question about Android being more secure from bad actors - there are most likely multiple parties that could be problematic (Google, device manufacturer, baseband manufacturer, network operator, etc.) while with Apple its just a single such entity.
What I meant is that on Android There is less being done to actively prevent their usage as a self hosting workstation (though some recent "security" changes communig from Google related to running code that does not come from an installed APK might be a reversal of that trend).
You can use a keyboard and mouse on recent iOS versions as well (and it works very comfortably on iPadOS). You can also connect an adapter to use a big screen.
I disagree with your argument that smartphones should be general-purpose computers. I don't think that having a smartphone be a general-purpose computer provides a significantly improved amount of control for 99.9% of the population.
Making a smartphone that does not behave as a general purpose computer is stuping and not to mention dangerous (as the manufacturer can always use it as a general purpose computer for its own nefarious means).