This is a really bad behaviour of PiHole uninstall script (not DietPi). We tried to convince PiHole devs to remove this question or change it into an information only. But without success unfortunately.
You are not the first one and you will not be last
https://dietpi.com/forum/t/dietpi-fail-to-find-eithernet-connection-at-boot-time/5254/1
https://dietpi.com/forum/t/removal-of-pi-hole-removed-ip-command-stuck-in-boot-net-wait/4976/1
PiHole GitHub issue https://github.com/pi-hole/pi-hole/issues/3929