So... Just here to post on how the online shield system works from excessive and careful testing and also some confirmation from TA themselves:
From the moment you log in you have a 3 hours long shield that will not care if you log off - it will keep counting down. The shield only resets after you log in again once someone views your network and the game recognizes that they did. it doesn't always recognize someone viewed your network - and you can test this yourself by asking a friend you trust to enter your network after your 3 hours are up and you'll notice that the game is not consistent at detecting when your connection has been hijacked and sometimes it won't recognize them at all until the brute force phase begins.
Things that are crucial to understand about how the online shield works:
You cannot reset the timer by simply logging out and back in again.
You are not protected by the shield if you log off and the timer will still keep counting down.
Your shield will not protect you past the 3 hour period, so simply leaving the app running indefinitely will not keep you protected.
Your connection can be hijacked once the 3 hour timer is up regardless of what you're doing, even if you're in the middle of a hack.
Your shield timer can be reset whether you're online or not.
Bonus: If you're too OP for playing the game all day everyday like I do for an excessive period of time - then the shield will eventually become faulty and not work properly anymore (currently I'm the only one affected by this and was told it's to protect "normal players" from me, so I no longer have the same consistent 3 hours long shield that everyone else does, meaning I get hacked more often now, RIP)
What's the take away from this? Well all of your suggestions would not really fix any issue and it would in fact bring more imbalance to the game instead. 12 hours is enough time for some to gather enough resources for big upgrades and log off with absolutely nothing, whereas 3 hours isn't enough for that and every player is open for attacks past that period. With the way it is now anyone can be hacked up to 8 times a day while they still gather resources and such, whereas all of your suggestions would only make players open for attacks once they've already spent the resources and log off with nothing - and then what's the point of hacking them anymore? The game would be full of dry and broke players and make progress even harder by taking even longer to gather resources. Even if the total online time was 6 hours, the timer still resets at a given time globally, so then for end game upgrades you could technically double the length of your shield by playing 6 hours before the reset time and after that immediately have another 6 hours to work with.