I think sin depends on more on the condition of the heart, not on the externals. My mum doesn’t bother with make up much (partly due to being a bit allergic to it). My wife and daughter like to do nice make up, but not out of vanity, just because they like to...
I had a thought that as Eve (before the Fall) was likely more beautiful and less likely to benefit from make up that women today, doing great make up is in a sense just an echo of the beauty that God put in creation at the beginning. I can appreciate a beautiful woman in the same way as a great sunset or a cute dog - all evidence of the aesthetic beauty of God’s creative heart.
I actually see your point but IMO "echoing" God's creation would rather be expressed through not wearing make up at all and embracing our natural form since God made us as He wanted. As far as I know, sunset or puppy don't any any artificial means to be appreciated and found beautiful.
I'm not really fond of the idea of debating about Scriptures' characters attractiveness imo (assuming Eve was pretty or that post questioning whether Jesus was hot) . Such 'shallowness' has no place in the meditation of the Scriptures to me. Some character have been described as attractive (David if I remember right(?)) but if no such statements has been said about plenty other ones, I think that's purposeful. It's not relevant to their character (most were probably very common-looking but it wasn't remotely relevant to their purpose).
Also just a look on what make up culture has become is enough for me to be wary about it. It ended up being a grotesque manipulation of people's insecurities to push them reaching unattainable uniformized standards of "beauty".
Like you rightfully said, it totally depends of what's in our hearts. Some women won't be able to go outside without make up while for others it's just a handy tool to diminish some flaws and look more comely. Vanity is the main factor.
For me it's the latter (esp since my job requires to look 'professional'), but I'm looking for wearing less make up in the future (not that I'm wearing that much right now ; my routine consists of : shimmery liquid foundation + mascara+ brow coloured gel + a few highlighting). I'm learning to love me as I am but that's not easy...