Note how the daal doesn't have this problem. It seems that it is kerned differently. So either رزو should be the same, or the harakat should move above the kaaf when proceeded by رزو
Also note that tanween fath has the same problem.
Edit: so ءؤدذ all have a large space after them than رزو do. A big space isn't a good thing, especially when there aren't any harakaat so it's not needed, but it might be the easier solution.
Edit: a temporary workaround s/([رزو][َّ]+)(?=ك)/\1\u200a\u2060/g
mustafa0x
commented
1 year ago 
https://svelte.dev/repl/c0379933480d4271a414c91dfc0f3075?version=3.53.1
Note how the daal doesn't have this problem. It seems that it is kerned differently. So either رزو should be the same, or the harakat should move above the kaaf when proceeded by رزو
Also note that tanween fath has the same problem.
Edit: so ءؤدذ all have a large space after them than رزو do. A big space isn't a good thing, especially when there aren't any harakaat so it's not needed, but it might be the easier solution.
Edit: a temporary workaround
s/([رزو][َّ]+)(?=ك)/\1\u200a\u2060/g