Well, Galatians 2:7-8 say:
“7 But on the contrary, when they saw that the gospel for the uncircumcised had been committed to me, as the gospel for the circumcised was to Peter 8 (for He who worked effectively in Peter for the apostleship to the circumcised also worked effectively in me toward the Gentiles),” (Ga 2:7-8 NKJV)
Peter was called to preach the gospel mainly to his fellow Jews, here called "the circumcised." Paul was called to preach the gospel mainly to Gentiles, here called "the uncircumcised."
Colossians 2:11 is about spiritual circumcision:
“In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ,” (Col 2:11 NKJV)
This spiritual circumcision happens to every sinner who is converted and comes to know Christ as Saviour.
Regarding Philippians 3:3, it's helpful to look at it in context:
“2 Beware of dogs, beware of evil workers, beware of the mutilation! 3 For we are the circumcision, who worship God in the Spirit, rejoice in Christ Jesus, and have no confidence in the flesh, 4 ¶ though I also might have confidence in the flesh. If anyone else thinks he may have confidence in the flesh, I more so: 5 circumcised the eighth day, of the stock of Israel, [of] the tribe of Benjamin, a Hebrew of the Hebrews; concerning the law, a Pharisee;” (Php 3:2-5 NKJV)
There were false teachers in the early church, who were telling Gentile Christians that they had to be physically circumcised in order to be saved. Paul is warning the Philippian Christians against this, telling them that what matters is spiritual circumcision, not the circumcision of the flesh. This is even clearer in Romans:
“28 For he is not a Jew who [is one] outwardly, nor [is] circumcision that which [is] outward in the flesh; 29 but [he is] a Jew who [is one] inwardly; and circumcision [is that] of the heart, in the Spirit, not in the letter; whose praise [is] not from men but from God.” (Ro 2:28-29 NKJV)