This is my netplan from when during the first COVID lockdown I created a dual Wifi Access point with both a 2.4GHZ and a 5GHZ dongle. The Access point was dealt with by hostapd however I found the only way to enable the Wifi interfaces without making them client wifi devices was to name them in the ethernets. Probably not what you need but its another reference.
Worked fine however it didn’t have the bandwidth I required so moved my existing AP to the middle of the house to improve coverage.
network:
version: 2
renderer: networkd
ethernets:
eth0:
dhcp4: false
addresses: [192.168.0.10/24,192.168.0.1/24]
gateway4: 192.168.0.254
nameservers:
addresses: [192.168.0.254]
match:
driver: bcmgenet smsc95xx lan78xx
set-name: eth0
wlan1:
optional: true
wlan2:
optional: true
bridges:
br0:
dhcp4: false
interfaces:
- wlan1
- wlan2
addresses:
- 192.168.7.1/24
nameservers:
addresses:
- 192.168.7.1
parameters:
stp: true
forward-delay: 0