Insofar as there is such a thing as “Christian Law” it would include, at least in principle, that bling is sinful.
It’s scattered liberally in the New Testament: 1 Timothy 2:9-10 and 1 Peter 3:3-4 are rather blunt about it. It is included in the broader concept of not catering to the flesh nor conforming to the world: Romans 13:14, 1 Peter 2:11, Galatians 5:13, 1 John 2:16, Titus 2:11-12, 1 Corinthians 6:19-20, Romans 12:1-3, and James 4:6.
Is that enough proof-texting? Do you get the concept? I believe the fundamental issue is not that you cannot call attention to yourself, but that if do so, it should be on the basis of your character and personality, not your visible fleshly presence.
So, for example, there’s nothing at all wrong with being healthy, fit and athletic, but there is something wrong with putting it on display through fashion choices. I should not call attention to my appearance. The emphasis is on my personal presence regardless of how I look. People should be drawn by the Holy Spirit, not by any fleshly factor.
Thus, the western concept of “wearing your Sunday best” is wholly wrong headed. God is not insulted by you showing up to worship in rather common street clothes that make you look pretty much the same as everyone else. Distinguishing yourself visually with haute couture at church is a sin.
I’d venture to say this is harder for women than men, at least in the west. Whether it’s something internal to women’s minds or something socially imposed, is mostly irrelevant from what I can see. Whatever the source or cause, there’s lots of pressure to look a certain way, and often that way can be attention-seeking.