Khadas Edge-V Pro RK3399 and Khadas VIM 3 uses AP6398S which only work on 4.4 Linux kernel images for now.
Hopefully in future the wifi chip can be better support and then mainline Linux images can work with wifi. With mainline Linux you will have open-source working GPU acceleration for Linux based on the Panfrost/Bitfrost Mali drivers that are compatible with Rockchip(and I think Amlogic) but still wip.
But if you need wifi and can’t wait a few months until it’s available, it would be possible to buy a cheap Realtek wifi dongle and plug it into a USB port(of either Edge-V Pro or Vim3) but I’m not sure if extra steps are needed but most Realtek chips work well with mainline Linux.
The Khadas Edge-V RK3399 basic model uses AP6356 wifi for which there is currently mainline wifi support. You will most likely also need the IO board to use micro-sd cards to flash Linux images easily.
You will have to check on Khadas’s shop and all all the components you need to check the difference in price between Edge-V Basic/Pro and Vim3 and decide on the feautres you need for your situation.