Hi guys,
Bit late to the party, but I thought I'd post my solution anyways... With no less than 193 pixels I got the design just right on my iPhone 12 mini:
body { height: calc(100% + 193px); }
Cheers!
EDIT - I had set the viewport way off... I used "initial-scale=0.42". My bad! Just tried it with normal scale, and Safari fills te page and window nicely.