Fit to screen doesn't work on mobile?

I have a prototype that I want to test in my iPhone, using Chrome. The prototype has a different screen size than my iPhone, so I need it to fit the screen.

Also, I’ve set “Fit to screen” before sharing the link. Device is set to “None”. But it doesn’t work. It also doesn’t work in the Figma app.

This is an example of how I thought it was going to behave, by adding the black bars around:

Any ideas on this?
Thank you!

Did more testing and it seems like this is an iOS issue. Needs more testing, but on Android seems to be fine? Not entirely sure tho.