im trying to prototype a website on figma for a wide range of devices but ive always been doing only 1920x1080. which other breakpoints should i use?

I only make desktop and work out in my head what the other devices will look like. Desktop 3-4 columns, Tablet, 2. Phone 1.

Figma provides typical breakpoints as default frame sizes. Press F and then select a device from the right side bar.

At least one phone device and maybe a tablet, depending on the nature of your design.