"With Christ" means "along with Christ" in terms of function not "in the same place as Christ." Another interpretation by imagination from the eisegesis of Trinity world. This interpretation error is rooted in a complete disregard for how the Greek word syn is used in Greek and the contextual facts clearly reveal what Paul intended. The Greek word "syn" is often used in Scripture to indicate one person is "with" another, NOT in terms of being in the same place/location, but in terms of purpose and this is what Paul has in mind at Philippians 1:23. Paul desires to be "with" Christ in terms of purpose and will, joining with Christ in his sufferings, fellowshipping with his sufferings, and being conformed to the likeness of his death, in the very same way he uses syn at Romans 6:8 and Colossians 2:20. He also uses this word in the same way at Romans 8:17, 32. The word "with" (syn) at PhIlippians 1:23 is not referring to WHERE Paul will be; he is saying he wants to with Christ in terms of fellowshipping in his sufferings.

16 For the Lord Himself will descend from heaven with a shout, with the voice of the archangel and with the trumpet of God, and the dead in Christ will rise first. 17 Then we who are alive and remain will be caught up together with them in the clouds to meet the Lord in the air, and so we shall always be with the Lord. 1 Thessalonians 4:17

And he will send forth his angels with a great trumpet and they will GATHER TOGETHER HIS ELECT from the four winds, from one end of the heavens to the other. Matthew 24:31.

Now we request you, brethren, with regard to the coming of our Lord Jesus Christ and our gathering together TO HIM. 2 Thessalonians 2:1.

that I may know Him and the power of his resurrection and the fellowship of his sufferings, being conformed to His death in order that I may attain to THE RESURRECTION OF THE DEAD. Philippians 3:10-11

6 For I am already being poured out as a drink offering, and the time of MY DEPARTURE has come. 7 I have fought the good fight, I have finished the course, I have kept the faith; 8 henceforth there is laid up for me the crown of righteousness, which the Lord, the righteous Judge, will award to me ON THAT DAY and not only to me, but also to all who have loved HIS APPEARING.
2 Timothy 4:5-8.