You've got a well established point with each of your explanation on each question, kudos on the job well done.
I wish you all the best in overcoming the circumstances that hinders you early submission.
And about how to keep our keys, offline is indeed a good option, but you should try and keep it in a secret place where no other person can easily access it.
And to be on the safer side, because there are different harm that can befall hard copies, I'll suggest you also try an safe it online, either in cloud storage, eMail or good drive.
Yes I also have my keys stored on my email just in case. Thank you for your kind and encouraging words sir, I also hope to overcome these challenges soon. 😊