VLAN configuration issue on Ubuntu Server/ Ubiquiti UDM PRO

[kevincork]

I have Pi-Hole ruining on a raspberry pi 4 / Ubuntu server connected to a Ubiquiti UDM PRO, it's work fine on my LAN, but won't work in any VLANs

Firewall rules created :

WAN_OUT accept IP: Pi-Hole destination Port 53

LAN_IN accept all VLAN to Pi-Hole IP / Pi-hole Port

GUEST_IN > same as LAN_IN (one VLAN is guest)

on the Pi-hole web interface, I only have eth0 listed in the network tab

Still in Pi-Hole, I enabled Conditional Forwarding, with my LAN gateway IP

Am'I expected to enable DHCP in UniFi with the PI-hole address?

coming back in my Ubuntu Server (Pi-Hole), I don't have interfaces.d but 50-cloud-init.yaml

so far I did this :

ubuntu@ubuntu:~$ sudo mv /etc/netplan/50-cloud-init.yaml /etc/netplan/01-netcfg.yaml
ubuntu@ubuntu:~$ sudo nano /etc/netplan/01-netcfg.yaml

but I'm worried about the config I gonna enter (I only have SSH to connect to the Raspberry Pi 4 and I don't want to lost connection)

ubuntu@ubuntu:~$ ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether XX:XX:XX:XX:XX:XX brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether XX:XX:XX:XX:XX:XX brd ff:ff:ff:ff:ff:ff

Here is my curent 01-netcfg.yaml

  sudo nano /etc/netplan/01-netcfg.yaml
      GNU nano 4.8                                   /etc/netplan/01-netcfg.yaml                                             
    # This file is generated from information provided by the datasource.  Changes
    # to it will not persist across an instance reboot.  To disable cloud-init's
    # network configuration capabilities, write a file
    # /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
    # network: {config: disabled}
    network:
        ethernets:
            eth0:
                dhcp4: true
                optional: true
        version: 2

1. how can I set a static IP of 192.168.1.70 (only if required, I don't really mind having a dynamic IP as the network DHCP already have an IP assignment)
2. how can I add VLAN 20 IP range 192.168.2.1/24 and VLAN 30 192.168.8.1/24