There is absolutely no (good) reason we should be using “Gentile” in English; we should look to Luther’s German translation and simply use the words we already have in English for this Greek term (εθνος) — nation and heathen.
‘So that in Christ Jesus the blessing of Abraham might come to the Gentiles [sic], so that we might receive the promised Spirit through faith.’ (ESV)
‘That the blessing of Abraham might come upon the Gentiles [sic] in Christ Jesus, that we might receive the promise of the Spirit through faith.’ (NKJV)
‘Auf daß der Segen Abrahams unter die Heiden käme in Christo Jesu und wir also den verheißenen Geist empfingen durch den Glauben.’
‘Ut in gentibus benedictio Abrahae fieret in Christo Iesu ut pollicitationem Spiritus accipiamus per fidem.’
‘ἵνα εἰς τὰ ἔθνη ἡ εὐλογία τοῦ Ἀβραὰμ γένηται ἐν ⸉Χριστῷ Ἰησοῦ⸊, ἵνα τὴν ⸀ἐπαγγελίαν τοῦ πνεύματος λάβωμεν διὰ τῆς πίστεως.’