Switching to systemd-networkd instead of default dhcpcd

I am trying to setup my Raspberrypi 3B as a VPN tunneled access-point. Something like wifi (from router) to wifi (using hostapd) access-point without any ether-net connection.
I found a very good guide at: https://raspberrypi.stackexchange.com/questions/89803/access-point-as-wifi-router-repeater-optional-with-bridge, and following the whole guide, I was able to achieve what I set for in a fresh install of Raspian.

While following the same guide in DietPi 6.33.3 fresh install, the networking broke at the QuickSteps sections at: https://raspberrypi.stackexchange.com/questions/108592/use-systemd-networkd-for-general-networking/108593#108593.
As soon as I execute the following:

apt --autoremove purge ifupdown dhcpcd5 isc-dhcp-client isc-dhcp-common rsyslog

, the networking breaks and I loose my wifi connection forever.

2 questions :

  1. Is there a way to create a wifi AccessPoint which tunnels data through a VPN, while connecting to router through wifi(NOT ethernet. RaspAP didn’t work),
  2. If not, how is the networking different in DietPi, than in pure Raspian? I want to move from dhcpd to Debian networking.

Bump. Anyone?