Spez I'm doing nothing right now, so I don't mind giving you a hand with this if you want.
I've got two ideas that I think will work, although I'd need to see the site to check first.
Edit: Have you tried manually adding the icons with css?
I'm not using this particular extension thus I can't actually test anything for you, but I've manually added fa icons to a bunch of other elements without any issues, so I'm assuming this should work for you too.
First, add this particular fa 6 script to the head:
// Updated
<script src="https://kit.fontawesome.com/940400877f.js" async></script>
Next, if adding the above script hasn't already fixed the broken pagination icons, try this:
// Updated
button[aria-label="First"] .Button-icon::before {
content: "\f100"; /*FA DOUBLE LEFT ICON*/
font-family: "Font Awesome 6 Free"; /*SET FA VERSION*/
}
button[aria-label="Back"] .Button-icon::before {
content: "\f104"; /*FA ANGLE LEFT ICON*/
font-family: "Font Awesome 6 Free";
}
button[aria-label="Next"] .Button-icon::before {
content: "\f105"; /*FA ANGLE RIGHT ICON*/
font-family: "Font Awesome 6 Free";
}
button[aria-label="Last"] .Button-icon::before {
content: "\f101"; /*FA DOUBLE RIGHT ICON*/
font-family: "Font Awesome 6 Free";
}
#pagination-inputJump + button[aria-label="Jump"] .Button-icon::before {
content: "\f0e7"; /* FA PAPER PLANE ICON*/
font-family: "Font Awesome 6 Pro";