Making custom font work on IOS

Site URL: https://www.bigsmall.works/

Hello there, 

My custom font added with @font-face is still not working on IOS and possibly other mobile.

I've followed previous post advice and added woff files but not working. 

Strangely sometimes it's working eg. in places on the site H4 the new font works in others it's default. 

Any help much appreciated.  

------------------

@font-face {
    font-family: 'Bigsmall';
       src: 
         url('https://static1.squarespace.com/static/5ec25f573c6e4e277c79c525/t/5f200f7cb7a03742fc1c655a/1595936637013/NeueMontreal-Bold.otf'), 
         url('https://static1.squarespace.com/static/5ec25f573c6e4e277c79c525/t/5f200f8ed211d27f0f5f8d37/1595936654028/NeueMontreal-Bold.woff2') format('woff2'),
         url('https://static1.squarespace.com/static/5ec25f573c6e4e277c79c525/t/5f200f8998fe6764e848cfc4/1595936649925/NeueMontreal-Bold.woff') format('woff'),
         url('https://static1.squarespace.com/static/5ec25f573c6e4e277c79c525/t/5f200f8499156872c6ce144a/1595936644842/NeueMontreal-Bold.ttf') format('truetype');

  }
h1 {
  font-family: 'Bigsmall';
} 
h2 {
  font-family: 'Bigsmall';
} 
h3 {
  font-family: 'Bigsmall';
} 
h4 {
  font-family: 'Bigsmall';
} 
p {
  font-family: 'Bigsmall';
} 
.sqsrte-large {
  font-family: 'Bigsmall';
} 
.sqsrte-small {
  font-family: 'Bigsmall';
}
@media screen and (min-width: 1px) {
 
.header-layout-nav-right .header-nav-list {
display: none;
} 

.header-burger {
  display:flex;
}
  
.header--menu-open .header-menu {
opacity: 1;
visibility: visible;
}
h4 {
  margin-bottom: -10px !important;
}
hr { padding: 0.01px 0 0.01px 0; }
hr {
  margin-bottom: -10px !important;
}
hr {
  margin-top: -10px !important;
}

}
.header-menu-bg {background: black!important;}
.header-menu-nav-item > a {color: white!important;}
.header-menu-nav-item > a {font-family: 'Bigsmall';}
.mobile-bar-wrapper * {
   font-family: 'Bigsmall' !important;
}
h3 {
  font-family: 'Bigsmall', 'Bigsmall', genericfont;
}