well this is interesting…
If you right-click Last Epoch in your Steam games and select Properties and choose Play Full Offline from the drop-down list in the Launch Options section of the General tab then you’ll be able to play offline during this 24hr maintenance period before Cycle 1.1 launches.
You where never playing in full offline mode from the start.
Game has 2 offline modes one still requires internet due to it still having global chat
2nd one can be accessed from the steam pop up as long as u didnt click always launch with this option (online) otherwise u have to do what andrew said
Of note I have my Steam launch settings for fully offline mode and it’s really easy then to use either. If I launch from the windows shortcut for the game, it launches normally with chat, the option to play online or off, the whole shebang. If I want to or need to do fully offline for example due to a server issue, I open Steam, launch from there, and away it goes. So it’s not like you need to modify your launch options every time or anything like that.