Westcott and Hort / [NA27 variants] πιστὸν ὄντα τῷ ποιήσαντι αὐτὸν ὡς καὶ Μωυσῆς ἐν ὅλῳ τῷ οἴκῳ αὐτοῦ.
Here is the context:
3 Therefore, holy brothers, you who share in a heavenly calling, consider Jesus, the apostle and high priest of our confession, 2 who was faithful to him who appointed him, just as Moses also was faithful in all God’s house. 3 For Jesus has been counted worthy of more glory than Moses—as much more glory as the builder of a house has more honor than the house itself. 4 (For every house is built by someone, but the builder of all things is God.) 5 Now Moses was faithful in all God’s house as a servant, to testify to the things that were to be spoken later, 6 but Christ is faithful over God’s house as a son. And we are his house, if indeed we hold fast our confidence and our boasting in our hope.
The Holy Bible: English Standard Version. (2016). (Heb 3:1–6). Wheaton: Standard Bible Society.
BDAG suggest "to him who appointed him". Is it compelling?:
...ⓑ of divine activity, specifically of God’s creative activity create (Hes., Op. 109; Heraclitus, Fgm. 30 κόσμον οὔτε τις θεῶν οὔτε ἀνθρώπων ἐποίησεν, ἀλλʼ ἦν ἀεὶ καὶ ἔστιν καὶ ἔσται; Pla., Tim. 76c ὁ ποιῶν ‘the Creator’; Epict. 1, 6, 5; 1, 14, 10; 2, 8, 19 σε ὁ Ζεὺς πεποίηκε; 4, 1, 102; 107; 4, 7, 6 ὁ θεὸς πάντα πεποίηκεν; Ael. Aristid. 43, 7 K.=1 p. 2 D.: Ζεὺς τὰ πάντα ἐποίησεν; Herm. Wr. 4, 1. In LXX oft. for בָּרָא also Wsd 1:13; 9:9; Sir 7:30; 32:13; Tob 8:6; Jdth 8:14; Bar 3:35; 4:7; 2 Macc 7:28; Aristobulus in Eus., PE13, 12, 12 [pp. 182 and 184 Holladay]; JosAs 9:5; Philo, Sacr. Abel. 65 and oft.; SibOr 3, 28 and Fgm. 3, 3; 16; Just., A II, 5, 2 al.) w. acc. ἡ χείρ μου ἐποίησεν ταῦτα πάντα Ac 7:50 (Is 66:2). τοὺς αἰῶνας Hb 1:2 (s. αἰών 3). τὸν κόσμον (Epict. 4, 7, 6 ὁ θεὸς πάντα πεποίηκεν τὰ ἐν τῷ κόσμῳ καὶ αὐτὸν τὸν κόσμον ὅλον; Sallust. 5 p. 10, 29; Wsd 9:9; TestAbr A 10 p. 88, 21 [Stone p. 24]) Ac 17:24. τὸν οὐρανὸν καὶ τὴν γῆν (cp. Ael. Aristid. above; Gen 1:1; Ex 20:11; Ps 120:2; 145:6; Is 37:16; Jer 39:17 et al.; TestJob 2:4; Jos., C. Ap. 2, 121; Aristobulus above) Ac 4:24; 14:15b; cp. Rv 14:7. τὰ πάντα PtK 2 p. 13, 26 (JosAs 12, 2; Just., D. 55, 2; also s. Ael. Aristid. above). Lk 11:40 is classed here by many. Of the relation of Jesus to God Ἰησοῦν, πιστὸν ὄντα τῷ ποιήσαντι αὐτόν=appointed him Hb 3:2 (cp. Is 17:7).—W. a second acc., that of the predicate (PSI 435, 19 [258 B.C.] ὅπως ἂν ὁ Σάραπις πολλῷ σὲ μείζω ποιήσῃ) ἄρσεν καὶ θῆλυ ἐποίησεν αὐτούς (God) created them male and female Mt 19:4b; Mk 10:6 (both Gen 1:27c).—Pass. Hb 12:27.—ὁ ποιήσας the Creator Mt 19:4a v.l....
Arndt, W., Danker, F. W., Bauer, W., & Gingrich, F. W. (2000). A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed., p. 839). Chicago: University of Chicago Press.