https://ramonvictor.github.io/body-scroll-freezer/
when testing on iPhone 6
some weird left margin for overlay - i.e. overlay horizontally doesn't fill all the screen, it leaves a noticable area uncovered.
...From the size of it it's about as big as desktop scrollbar...
Same with Android Brave. Also - on Android Brave things it doesn't work with weird margin bottom, weird size of textarea. When Modal appears, it doesn't look as modal.