Revelation 20:4 (Beheading?)

Revelation 20:4 (ESV): "Then I saw thrones, and seated on them were those to whom the authority to judge was committed. Also I saw the souls of those who had been beheaded for the testimony of Jesus and for the word of God, and those who had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ for a thousand years."

SBLGNT: Καὶ εἶδον θρόνους, καὶ ἐκάθισαν ἐπ’ αὐτούς, καὶ κρίμα ἐδόθη αὐτοῖς, καὶ τὰς ψυχὰς τῶν πεπελεκισμένων διὰ τὴν μαρτυρίαν Ἰησοῦ καὶ διὰ τὸν λόγον τοῦ θεοῦ, καὶ οἵτινες οὐ προσεκύνησαν τὸ θηρίον οὐδὲ τὴν εἰκόνα αὐτοῦ καὶ οὐκ ἔλαβον τὸ χάραγμα ἐπὶ τὸ μέτωπον καὶ ἐπὶ τὴν χεῖρα αὐτῶν· καὶ ἔζησαν καὶ ἐβασίλευσαν μετὰ τοῦ χριστοῦ [a]χίλια ἔτη.

Commentary: "The martyrs in chapter 6 were said to be 'slain' or 'slaughtered.' Here they have been beheaded. They are actual martyrs because in John's visions all faithful Christians have been killed. They are not an elite group that is more 'spiritual' than other believers. The further description of them as those who had not worshiped the beast or his image and had not received his mark on their foreheads or their hands (v. 4) places the accent not on their martyrdom as such but on the faithfulness that made martyrdom inevitable."

See https://www.biblegateway.com/resources/commentaries/IVP-NT/Rev/Reign-Martyrs

Albert Barnes: "That were beheaded - The word used here - πελεκίζω pelekizō- occurs nowhere else in the New Testament. It properly means, 'to axe,' that is, to hew or cut with an axe - from πέλεκυς pelekus 'axe.' Hence it means to behead with an axe. This was a common mode of execution among the Romans, and doubtless many of the Christian martyrs suffered in this manner; but 'it cannot be supposed to have been the intention of the writer to confine the rewards of martyrs to those who suffered in this particular way; for this specific and ignominious method of punishment is designated merely as the symbol of any and every kind of martyrdom'” (Prof. Stuart)."