The second commandment isn’t redundant. It does repeat the first command, but whereas the first command tells us not to worship false gods, the second expounds saying nor are we to worship God falsely. How you worship cannot be separated from who you worship. Methodology isn’t a piston that fires independently of theology. Methodology is theological. God speaks to His people revealing Who He is, and then, flowing from that, He informs them how He is to be worshipped.
They are not to make an idol and worship it as God, for idols tell lies. Idols are measurable, our God is infinite. Idols are created, our God is Creator. Idols can be controlled, our God is sovereign. Idols need, our God overflows. Idols were visible, our God is invisible.
And yet, the second member of the Godhead became flesh, the image of God. But how is He represented to us today? By the Word of God. Worshipping God in Spirit and in truth means that our worship is focused on Christ. Our worship being centered on Christ means the preeminence of the Word in Christian worship. Who? Christ. How? The Word. The church gathers simply to pray the Word, sing the Word, hear the Word, see the Word (in the sacraments), and preach the Word.
Our worship is never pure, but where methodology is gloried in and theology sidelined, where the visual receives applause and the audio of the preached Word is only tolerated, be certain that idolatry is underfoot.