you can definitely install retroarch on debian, it’s not a problem.
but they had to disabled core downloader to avoid piracy claims, so you need to enable in setting menu “core downloader” and only then download cores.
google ‘retroarch download cores’ or check this: RetroArch - Debian Wiki
also if you are planning to use uconsole’s “gamepad” I highly recommend to install QMK firmware for uConsole keyboard as it has “gamepad mode”