Well, I’m not going to hire a backend developer who doesn't have a reasonable understanding of data structures and algorithms. Just no. I want to be able to know that this person gets that scanning a list will take longer than scanning the equivalent sized tree for example.

That being said, I’m not looking for this person to have memorized various searching and sorting algorithms, to have written scholarly articles about them, or otherwise be a complete algorithm & data structure expert. We have books for that.

So yes you need to learn this, unless you just want to be a code jockey who does what others tell them to do, does no interesting design work, and who can’t grow and expand their abilities.

Not knowing data structures and algorithms is like a car mechanic who knows wrenches and screwdrivers, but doesn’t have any idea of how the ignition system or transmission works. This mechanic doesn’t need to know the physics of fire or the metallurgy of the transmission gears, but they need to have a reasonable idea of what’s going on.