I found out if you sideloading app using sideloady, and the app expired you can still use it without every 7 day to use pc sign again.
Other method sideloading I am not trying like scarlet or esign or other.
Even it expired, you can still use it. Make sure your app keep in multitasking or don't restart your phone. Mine has expired 5 days, because some busy so not every 7 day I borrow pc from my friend.
If has expired, you can not open the app from homescreen, try it from multitasking, it still can use it. Hope this can help.
here is the proof :
Here the proof I always keep it in multitasking and background app refresh always off
If this has post before or repost, let me know, I will remove it. I am sorry if I wrong section because this is my first post.