Right, but if AMD need to produce these chips and more people are working from home, thus more people are potentially buying laptops then a cut of the available chips could potentially still be going into laptops?

Leaving less available chips for desktops. Additionally, I've heard that prebuilt desktop builders are also in high demand for the chips.

No, generally desktop chips and laptop chips are entirely different products. For example, none of the Zen 3 AMD desktop chips have integrated graphics, while all of the laptop ones do. And with the way semiconductor fabrication is done, I believe that the volume of chips manufactured was planned well in advance, and pivoting from making one to making the other cannot be done quickly.