I've recently been doing a lot of reading up on the Moors and their time in Europe (like Al-Andalus) and I often see people say this? How true is this claim (if it even is true)? Is their influence overstated or not?
Not at all true. It's mostly based on long-debunked misconceptions about the European Early Medieval period, oddly colonialist rhetoric, and pure imagination over hard evidence to the contrary. There's a string of posts on the topic here