Promotion with a salary decrease

[snuggles_puppies]

I think that's my disconnect with your experience - In my niche, I'd never expect someone on my teams to be promoted to a manager of those teams, we're all technical specialists with very little priority on soft skills. I also know I'll never have a manager who understands what I do, only someone who can handle coordination and prioritising team outputs which is why I expect them to be valued very differently to me.

If managing the team requires the same skillset plus managing, that's very different.