Well, I've seen a lot of discussions which try to prove otherwise. But perhaps it also depends a bit on the level in Software Engineering? If you are new, it might be that back-end feels more complex.

But yeah, front-end even feels harder to debug at some points like the one I mentioned in the OP, at least for me. Not to mention the facts you keep overthinking what might be a good solution in terms of UX (in case that too many DOM elements is the issue of slow performance).