Believers already have eternal life.

Eternal life is a recurring theme in the first half of the Fourth Gospel, with Jesus declaring in John 5:24 that whoever hears his word and believes in the one who sent him has eternal life, passing from death to life without facing judgment. This idea is reaffirmed in John 6:47, where Jesus tells his disciples that believing in him brings eternal life. The same message is conveyed in verses 16 and 36, emphasizing that believers have already received the gift of eternal life. Receive this gift in the future. It is the present possession of all who believe. Anyone who truly believes already has eternal life.
You may now think: Why then do deeply believe Christians die? To understand this, we must realize the biblical distinction between eternal life and immortality. We already own the first one. The latter is something we will receive only at the second coming of Jesus Christ. Paul wrote that “when the trumpet sounds, the dead will be raised incorruptible, and we will be changed.” Only then will death be definitively defeated. (1 Cor 15:51-55)
The essence of the matter is that before eternal life occurs, people face the first death – as a result of which they sleep in graves for some time. Immortality means that whoever obtains it will no longer be subject to death in any form. A Christian already has eternal life, but he will become immortal only when God gives him this gift at the end of earthly history.

Those who reject the Son of God will be denied the gift of immortality, perishing in the consuming fire rather than suffering eternally in God’s presence (2 Thess 1:9; Mal 4:1; Rom 6:23; Rev 20:14).

Notably, John 3:36 reveals that God’s anger is distinct from human malice, a measured attitude that will ultimately end the existence of this sinful world, where the innocent currently suffer.

This is how the “wrath of the Lamb” is described in Revelation 6:16.
The best message from John 3:36 is that each of us can freely choose eternal life.