Circular Doubly Linked List

While a circular doubly linked list is an interesting data structure, this is a slightly strange site/resource - at least as far as algo/ds go.

Perhaps I am being too harsh, but the site is "alphacodingskills" yet appears to teach just the very basics of various languages. Additionally, all of the algorithms on the site are sorting algos (except one). For data structures it's just stack/queue/and variations of linked list

I'm not sure if I were to only know the basics of say Java, how to sort various ways, & basic ds that I will have "alpha" coding skills, or pass a rigourous FAANG-style technical interview (there is an interview question section on the site).

Edit: Overall it's a promising resource, IMO it just needs more content to be a serious one.