Hi Sarina,
Yes, apple devices seem to have issues with fixed backgrounds. As far as I know, there’s no workaround yet CSS-wise.
The link you provided is a fix in the sense that it no longer sets the background to “parallax”. It just reverts to normal behavior.
The code for that relevant to the Block you used is this:
@media (min-width: 769px) and (max-width: 1024px) {
.wp-block-cover.is-light.has-parallax > .wp-block-cover__image-background.has-parallax {
background-attachment: scroll !important;
background-size: cover;
height: 100%;
overflow: hidden;
}
}
This will work on all tablet devices though.