The two groups of 144 000

Tim,
According to your teachings, there are two groups of 144 000 in Revelation:

1. The sealed at the beginning of the tribulation: [Rev 7:3-4 NKJV] “Do not harm the earth, the sea, or the trees till we have SEALED the servants of our God on their foreheads. And I heard the number of those who were sealed. One hundred [and] forty-four thousand of all the tribes of the children of Israel [were] sealed:”

2. The firstfruit at the end of the tribulation: [Rev 14:1, 4 NKJV] Then I looked, and behold, a Lamb standing on Mount Zion, and with Him one hundred [and] forty-four thousand, having His Father’s name written on their foreheads. … These are the ones who were not defiled with women, for they are virgins. These are the ones who follow the Lamb wherever He goes. These were redeemed from [among] men, [being] FIRSTFRUITS to God and to the Lamb.

1. Is group 1 the same as those who will repent to God by reinstalling the sacrificial service? Is it ”the remnant” of [Rom 9:27 NKJV] “Though the number of the children of Israel be as the sand of the sea, The REMNANT will be saved.”? Is it ”the remnant” of [Isa 10:21 NKJV] ”The REMNANT will return, the remnant of Jacob, To the Mighty God.”?

2. Is group 2 ”all Israel” which are saved at the return of Christ? [Rom 11:25-26 NKJV] ”Blindness in part has happened to Israel until the fullness of the Gentiles has come in. And so ALL ISRAEL will be saved, as it is written: “The Deliverer will come out of Zion, And He will turn away ungodliness from Jacob” (If so, does the period ”the fulness of the Gentiles” end at the return?)

Thank you! /Anders