photoshop – Why do my colours completely fade when I merge layers or export to jpeg?

I’ve been working on a colourful image but when I export it to jpeg, the colours are almost gone. Sure, I understand saving in jpeg can lead to change in colour but.. this is the most massive loss of saturation I’ve seen. The same thing happens if I merge down as well.

This is what my layers look like

enter image description here

Am I missing something obvious?

The difference:

left is the file still in PS and right is my jpeg

The purple colour especially seems to not appear. I feel like I’m missing something obvious. Am i working in the wrong colour space?

How can I get the colours to pop in my export files?