en_tn_lite_do_not_use/gal/01/08.md

But even if we or an angel from heaven should proclaim ... let him be cursed

Paul said this to show how strongly he felt about anyone who might proclaim a gospel other than the one he had proclaimed. If anyone would do that, that person should be cursed. Alternate translation: "But even if we or an angel from heaven were to proclaim ... let him be cursed"

But even if we or an angel from heaven should proclaim

The word "even" shows that Paul did not believe that they or an angel from heaven would ever proclaim a different gospel. But he includes himself and angels in his statement to emphasize how wrong it would be for anyone to proclaim a different gospel.

other than the one

"different from the gospel" or "different from the message"

let him be cursed

"God should punish that person forever." If your language has a common way of calling a curse down on someone, you should use that.