Almost all wireless cards require non-free firmware to work and Debian cannot include this in their official release because it violates their social contract.
See also https://wiki.debian.org/Firmware
To get the wireless device working in the installation phase see the official installation guide:
https://www.debian.org/releases/buster/ ... 04.en.html
Please link to this thread when replying to all firmware-related wireless queries so that it shows up in search engines, thanks.