There is a difference in text of Eph 4:9 between the ancient witnesses and the later Byzantine text which (in this case) the Tr follows:
Ancient witnesses
τὸ δὲ Ἀνέβη τί ἐστιν εἰ μὴ ὅτι καὶ κατέβη εἰς τὰ κατώτερα μέρη τῆς γῆς; = Now what is "He ascended," except that He also descended into the lower regions of the earth?
Byzantine text
Tὸ δέ, Ἀνέβη, τί ἐστιν εἰ μὴ ὅτι καὶ κατέβη πρῶτον εἰς τὰ κατώτερα μέρη τῆς γῆς; = Now what is "He ascended," except that He also descended first into the lower regions of the earth?
Note that the Byzantine text has an added "first" about which Bruce M Metzger in his "Textual Commentary on the GNT" offers these comments:
The addition of πρῶτον after κατέβη (Sinaiticus [third correction], B C K P 88 614 Byz etc) appears to be a natural expansion introduced by copyists to elucidate the meaning. The shorter text is strongly supported by P46, Sinaiticus[uncorrected] A C D G 179 al.
UBS5 rates the probability of the original text without "first" as {A} = almost certain. For more details about which MSS support which text, see UBS5.
Most modern translations follow the UBS5 text including: NIV, NLT, ESV, NASB, BSB, BLB, NASB, CSB, HCSB, CEV, GWT, ISV, NET, NHEB, ASV, FV, Darby, ERV, LET, DRB, etc
Among the translations that follow the Byzantine text are: GNT, KJV, NKJV, WEB, AKJV, LSV, YLT, etc.