When I export out of Lightroom, these "lightlines"

The background moire? You sure that wasn't there before?

Try exporting in a larger file size, that could help. JPEG has a bit of a tendency to create this. But I think LR still doesn't support BPG or WEBP or FLIF plus wherever you publish might not accept these anyhow, right?

Using the noise reduction and sharpening liberally as some JPEG pre-processor of sorts could also could do the trick.

>>3029184
https://en.wikipedia.org/wiki/Moir%C3%A9_pattern
https://en.wikipedia.org/wiki/Aliasing

twp things you could try
1. export at the original resolution, or at an integer multiple
2. in your export settings, turn off "sharpen for...(print, screen, etc)"

let me know if this doesn't fix your problem. i'm interested in this, because lightroom shouldn't be making these artifacts.

>>3029184
looks like a mix of aliasing and a grid coming from bad debayering