https://www.digitaltrends.com/gaming/how-to...are-on-ps4/?amp

So I just discovered the existence of gameshare. Currently im planning to share my game library with one my close friend. And in the future a third person which is my younger sibling once the ps5 are available as i want to pass my ps4 to them.

So reading the article in the link above, i have a few question:
1) why i need to designate my friend console as the primary account? Can't i make my own console as primary for the gameshare to work? It's just that i feel more comfortable knowing the primary account are in my own console.

2) In the event that my account are install in 3 console, which is mine, my friend, and my sibling, what would be considered as a banned/blocked from accessing the account? Is it 3 person accessing the same account at the same time? Or is it 3 person playing the same game in the same account at the same time?

3) Any security measured that i can take to avoid people acessing psstore or buying stuff under my account or changing important stuff like account detail?

1) https://forum.lowyat.net/index.php?act=ST&f...post&p=92904920

You can play your own content if you login your own profile on anybody's PS4 console, even without making your PSN account as the primary account on any PS4 console.
This does not apply to PS3 & PSVita as you need to activate the hardware on your PSN account.

Making an account primary on a PS4 console means you are allowing ALL users on this specific console to use that primary account's content.

2) https://www.playstation.com/en-gb/get-help/...ation-4-system/

Only 1 PS4 can be set as primary at 1 time.
The game owner's icons "Start" has a padlock icon beside it, if it is not primary while logged on as other users profile in that console.

So maximum only 2 persons can play the game at the same time.
1 is yourself when logged on to your profile on your console without your primary activated, 2nd is your friend logged on to his profile on his console but with your primary activated and using your purchased game (he didn't buy it).
This part still OK.

If 3rd or 4th person want to start the game using his own profile and his own console with your game installed, they can't because your primary is activated on your friend's console.
He can logout his own profile and then login your profile, but this will usually cause you to be logged out from your console immediately and maybe will start activate Sony's auto ban due to suspicious logins from 3rd/4th console hardware when you tug-of-war login your profile on your console vs 3rd/4th person's consoles.

3) You need to enable password confirmation for purchases in your profile Settings.

Thank you for the clear explanation. Much appreciated