Will PlayStation ban you for game sharing?
Not always, if rarely at all. Like Tyrant said, don't risk it if you don't wanna worry about it. There's a good reason why it can be bannable, and that relates to the recovery of your account/the person with the games you're borrowing from.
Is it possible to share PS Plus subscription?
Yes, PS5 accounts can share PS Plus. However, this is limited to just one console. You will not be able to share PS Plus across accounts on different consoles.
Is game sharing on PS legal?
That means you can essentially digitally lend someone your game, but you can't play at the same time. (And no, game sharing is not illegal on the PS4.) Both users need a PlayStation Plus subscription.
Can I share PS Plus with 2 friends?
You don't count your own console when you're using the account that owns the games/subs. Youre sharing with one friend. You can't share with 2 friends unless one is on ps5 and the other is on ps4.