list manipulation – Applying transformation rule for corresponding indices?

I have two lists, that looks like below

list1 = {a, x, b, x, x, c};
list2 = {2, 3, 4, 5, 6, 7};

Any time there is an x in the first list (list1), I want to replace it with the corresponding element in the second list (list2).

Any suggestions on nice ways to go about doing this?


I realize this should be simple with a loop (get the length of the lists, let the loop iterator be the index, and just compare and replace element by element)

However, I believe its usually better to use Map, MapThread, or take advantage of Listable attributes. I don’t see how I can do so here, but feel there might be a simple way?

Perhaps something with MapIndexed as mentioned here


Edit: The best way I can come up with is below. It still requires using a local environment Module though, which I feel like might be avoided by a better approach.

Module({rules, keys},
 keys = Flatten@Position({a, x, b, x, x, c}, x);
 rules = AssociationThread(keys -> {2, 3, 4, 5, 6, 7}((keys)));
 ReplacePart({a, x, b, x, x, c}, rules)
 )

Edit 2:
I have realized my question is perhaps a duplicate of this old question, but answers have just been posted here so I will not delete my question. Sorry for the confusion and mistake.