“to live is Christ” must mean that Paul so totally wanted to glorify Christ that as long as he lived everything about him was to point people to Christ
While living on earth, Paul longed:
to see salvations
to see people grow as disciples
to see Christ made famous
Isaiah 26:8 “Yes, Lord, walking in the way of your truth, we wait eagerly for you; for your name and your renown are the desire of our hearts.”
Isaiah 26:8 NAC
They knew that their future was tied to God, so if he is glorified, they will be just fine.