[2020] Friend gave me an account

Potentially.

More importantly you're doing yourself a disservice. You won't be able to celebrate your successes, as they have been earned by someone else. You won't be able to reminisce about early content, as it was done by someone else. You won't know where you did x/y/z if it comes up, as it was done by someone else.

Additionally, as the account is not yours it could be reclaimed. Meaning you would lose all your progress and all the money you've put into the account.

I would recommend you create your own account and enjoy the game from the start yourself. There are many guides and helpful people who can help you find the best ways to level to get to the content that you want to reach and best of all you'll be able to feel the pride of getting there yourself.

I'm honestly not the best person to ask for rule specifics. It is against the rules however.

Ultimately if you're using someone else's account then you're not playing your own game. You get no right to feel pride in your achievements because they simply aren't yours. You also risk your account getting locked or banned and if you forget your password, or it gets automatically reset for whatever reason, then in all likelihood you've lost the account. It's just not worth it.