Unity UI Text size based on resolution/ppi

Hello everybody,
I'm writing some code that will run on both iOS and Android smartphones and tablets. I'm having issues understanding how to handle text.

I have a screen canvas (Scale with Screen Size). All my boxes are anchored around the canvas in order to resize on different resolutions. All my texts components have Auto Size checked, and I've set a maximum size of 95. I can't know in advance how the text will look because I load it all from files during runtime.

My problem is that if I test the code on an iPhone SE (1136x640, 326ppi) the readability of the text is good enough, but on an iPad Air (2048x1536, 264ppi) it's way too big.
I figured that maybe I should set the maximum size of texts during runtime, based on the ppi maybe, I just can't figure out how. I thought that Scale with Screen Size would have been enough to make it work.

Thanks in advance for any help.

 

Anyone?

I'm running some tests, and apparently the number of dpi is relevant until a certain point.
I set a "base level" of text size, let's say my title has size 90 for a 326 dpi device, and when I launch the application I compute a factor (Screen.dpi / base_level_dpi) and multiply it for the text size. It works fine on iPad (lower dpi), but the text size increases too much on devices with a higher number of dpi (640 dpi, Samsung S7). Apparently, the readability is still good without this trick on the S7.

So, it makes sense with device with lower dpi value, but not with higher. What am I missing?
Thanks again.