The premise of having eternal life now (or God giving eternal life to His sheep) should be conjoined with eternal life being a personal noun
1 John 5
20And we know that the Son of God has come and has given us understanding, so that we may know Him who is true; and we are in Him who is true—in His Son Jesus Christ.
He is the true God and eternal life.
John 11
25Jesus said to her, “
I am the resurrection and
the life. Whoever believes in Me will live, even though he dies.
If Jesus is eternal life, which He is, then Eternal life was in the Virgin Mary at one point, in a sense, then left her body, yet continued to be eternal life. Therefore eternal life leaving someone's body
in itself does not stop it from being eternal life, no?
Also note that Peter had received the Holy Spirit in Acts 2:4, yet
Galatians 2
11When Cephas came to Antioch, however, I opposed him to his face, because
he stood to be condemned.
12For before certain men came from James, he used to eat with the Gentiles. But when they arrived, he began to draw back and separate himself, for fear of those in the circumcision group.
It seems to me therefore there are two choices, to take heed, or to resist, pretend it is not obvious what that means, and do backflips trying to make that fit your interpretation of certain scriptures
But further, the Galatians Paul was talking to obviously had the Holy Spirit. One merely has to note the difference between this scripture:
Galatians 3
3Are you so foolish? After starting in the Spirit, are you now finishing in the flesh?
And this non-scripture:
Are you so foolish? After
not starting in the Spirit, are you now finishing in the flesh?
There are other places as well (Galatians 3:5, Galatians 4:6), yet, believing they had the Holy Spirit, Paul gave this warning which imo answers the OP most clearly
Galatians 5
2Take notice: I, Paul, tell you that if you let yourselves be circumcised, Christ will be of no value to you
at all.
3Again I testify to every man who gets himself circumcised that he is obligated to obey the whole law.
4You who are trying to be justified by the law have been severed from Christ; you have
fallen away from grace.
Here's the Greek
https://biblehub.com/text/galatians/5-2.htm
https://biblehub.com/text/galatians/5-3.htm
https://biblehub.com/text/galatians/5-4.htm
Also, I encourage you to read Romans 1:1 to Romans 3, or all of Romans for that matter, and determine for yourself that this verse was speaking indiscriminately about everyone who does these things, and not just those under the law
Romans 2
6God “will repay
each one according to his deeds.”
7To those who by
perseverance in doing good seek glory, honor, and immortality, He will give eternal life.
Cross reference
John 5
28Do not be amazed at this, for the hour is coming when
all who are in their graves will hear His voice
29and come out—those who have done good to the resurrection of life, and those who have done evil to the resurrection of judgment.
Again, Peter could have continued to discriminate. The Galatians could have gotten circumcised, and were also warned to not practice these things
Galatians 5
19The acts of the flesh are obvious: sexual immorality, impurity, and debauchery;
20idolatry and sorcery; hatred, discord, jealousy, and rage; rivalries, divisions, factions,
21and envy; drunkenness, orgies, and the like.
I warn you, as I did before, that those who practice such things will not inherit the kingdom of God.