LXC container - Ubuntu22.04 and UP no longer have LAN connetion

[AreYouLoco]

You didnt provide any error message nor logs so I based on this that worked in the past:

LXC container veth interface gets disabled

Try to compare settings in LuCi Network-> Interfaces → Devices Compare br-lan and br-lab if they have the same settings.

Maybe you didnt wait long enough for the container to get IP or you could force it with dhclient. Just guesses here