It's in no order, play whichever one you want first
Backup the saves, uninstall the game and install the new apk
Yes
The password isn't in the trinity quests, try to remember any passwords mentioned in the main storyline
Replay the trinity scenes and make sure to write down stuff that seems important. Good luck!
If you upgrade to Android 11, that happens, don't know why though
This game is not for you then. The way the story progresses already shows that it won't be a regular dating sim, if that's what you're interested in. Personally, I love the way the author is telling the story and I wouldn't have it any other way.
The answer is in the third trinity scene.
