Good to see that it works. You boot from SD card, right? Because from eMMC it doesn’t seem to work: Rock 4 C+ Dietpi Support?
This seems to be the CYW43455 WiFi chip, the same used (onboard) on my PINE64 SOQuartz module. Actually I think its even the same module. For his image we needed to add some firmware text file from upstream kernel, as the blobs are already provided by Debian’s Broadcom firmware package: Debian -- Details of package firmware-brcm80211 in bullseye
curl -sSf 'https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/brcm/brcmfmac43455-sdio.AW-CM256SM.txt' -o /lib/firmware/brcm/brcmfmac43455-sdio.txt
However, I thought I saw this exact file being part of the armbian-firmware package already:
dpkg -S brcmfmac43455-sdio.txt
To quickly check whether the hardware is detected:
ip l
If no wlan0 shows up, no need to try with dietpi-config. The kernel should actually show related error messages, providing possibly more hints:
dmesg -l 0,1,2,3