My idea for a solution would be to offer better pay/benefits opportunities for your good developers, at the same time giving them also more creative freedom when they rise the ranks in a technical role.

Making management the only option for having a "career" is the issue.

Another option to avoid the downsides of the Peter Principle is to test drive people in their new roles. Basically you slowly add responsibilities that look more like the post-promotion job, if they do well they get the promotion and they've already proven to be able to do these things. If at some point you notice it isn't working, well then you don't promote them, or promote them to a different position.

This was famously discovered 60 years ago:

https://en.wikipedia.org/wiki/Skunk_Works

> The designation "skunk works" or "skunkworks" is widely used in business, engineering, and technical fields to describe a group within an organization given a high degree of autonomy and unhampered by bureaucracy, with the task of working on advanced or secret projects.

One of the key findings of the Skunk Works project is that you unlock potential, a company needs to be willing to pay individual contributors more than their managers.