Yes. It IS small. Because of it being a 6.4" screen with 1080p resolution.
You actually shouldn't (Although it's a GSI so it didn't know the device dpi, so you gotta set it manually).
Just set the default native dpi of your display (409) & instead lowering it, try to increase font size. That's the best experience to get the plenty of workspace with ample font size to read to.
Same goes to computers. Instead of messing with resolution & dpi, it's better to increase icons & font sizes.
It's funny that when you have 409dpi, the 40dp status bar that I had actually looks better, infact more smaller than the punch hole calculations you did.