You can use js for prevent scroll:
let body = document.body;
let hideScroll = function(e) {
e.preventDefault();
};
function toggleScroll (bool) {
if (bool === true) {
body.addEventListener("touchmove", hideScroll);
} else {
body.removeEventListener("touchmove", hideScroll);
}
}
And than just run/stop toggleScroll
func when you opnen/close modal.
Like this toggleScroll(true) / toggleScroll(false)
(This is only for iOS, on Android not working)