My stockfish takes a little less than 2 seconds to find it.
If the engine runs server side, then with tens of thousands of users of course they're not going to give much computing power to you. They may have a strong engine, but if it only thinks for 0.5 seconds it's not going to find the best move.
Anyway, since these engines are free, and the interfaces that allow you to use them are free, I don't know why people don't just download this stuff. Using analysis on a website is going to give you very sub-par results.
I was watching Agadmator's videos and he did one on Leko vs Kramnik where in this position