If the you is a second person pronoun. Then it means anyone who reads it the you is directed at them. So it can be the whole world or anyone that reads it.
No, only those chosen by God unto salvation.
[2Th 2:13 KJV]
13 But we are bound to give thanks alway to God for you, brethren
beloved of the Lord, because
God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth:
The term "us-ward" (v9) is defined by the word "beloved"; v8, the word "beloved", are those addressed in salutation of the book.
[1Pe 1:1-2 KJV]
1 Peter, an apostle of Jesus Christ, to the strangers scattered throughout Pontus, Galatia, Cappadocia, Asia, and Bithynia,
2
Elect according to the foreknowledge of God the Father, through sanctification of the Spirit, unto obedience and sprinkling of the blood of Jesus Christ: Grace unto you, and peace, be multiplied.
[2Pe 3:8-9 KJV]
8 But,
beloved, be not ignorant of this one thing, that one day [is] with the Lord as a thousand years, and a thousand years as one day.
9 The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to
us-ward, not willing that any should perish, but that all should come to repentance.
[1Jo 3:1-2 KJV]
1 Behold, what manner of love
the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not.
2
Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is.
[Col 3:12 KJV]
12 Put on therefore,
as the elect of God, holy and beloved, bowels of mercies, kindness, humbleness of mind, meekness, longsuffering;