" you have less control."

Keyboard and mouse don't give you any more autonomy over the application developers state machine.

I'm not sure I understand the claim of "being in control". The UX is different, sure, often. But that's not "control" over the design of the application.

I feel so constricted and frustrated when I have to use my phone. I often even put things off until I can get back to my computer.

On a touchscreen, I can tap. That's it. Select? Tap. Move? Tap. Highlight? Tap. The only one that makes sense is draging for moving, but even that's a pain in the butt because it often misinterprets the tap+hold duration that's necessary before it works. When I'm editing text (navigating, cut-n-paste, etc.), it gets what I want wrong more often than it gets it right, I mean like 80/20.

With the phone, they had a green field to design an entirely new UX for touch interfaces, so there's no legacy to blame.

Sure they do, with KB/M against a browser app you can open the dev console, you can inspect element, you can do all sorts of things that you can't do in a native app for touchscreen only.