It may be non-trivial to dig yourself out of a performance hole if you didn’t account for performance at all in the design. The pervasive idea that you can make it fast later virtually never pans out.

In many cases, taking performance into account up front adds little overhead and won’t appreciably affect the design. But, if you codify some algorithmically inefficient approach into your public API, you’re going to find that hard to unwind. The engineering team should advocate for that when designing the product.