If you know how to install crown molding, you can install the molding a few inches below the ceiling line and stick lights up just inside the top.

https://imgur.com/a/ZpBXbom

Looks good. Do they make more modern styles of crown molding? Maybe something with more rectangular stock?

Easiest way would be to get some tracks with diffusers. Kind of like this:

https://www.amazon.com/StarlandLed-Aluminum-Installation-Professional-Accessories/dp/B01LL3S006?th=1

Could it be possible to paint the track white so the edges of it don’t stand out as much?

You can buy thin metal profiles with plastic cover, they are produced exactly for lighting strips purpose. I used that for my kitchen, looks professional and covers all the wiring. something like that

This kit has endcaps.

I mean the edges of where the diffuser snaps into the track

Search "art deco" or "contemporary" crown molding for more geometric designs.

You could also just use a simple profile like this. It's not rectangular, but it's less ornate and more modern-looking.

Thanks

There are companies that make crown molding specifically for LED strips in all kinds of different shapes. Just Google "led crown molding" and it should be obvious