I've only experienced a non-technical manager once - maybe this more common in older, more traditional companies. I don't agree that a manager should spend 80%

I've only experienced a non-technical manager once - maybe this more common in older, more traditional companies. I don't agree that a manager should spend 80% of their time coding, though. Maybe for smaller teams at early stage startups. But for even a team of 4-5, there are typically things they should be doing that are a better use of their time. It helps to code part of the time (maybe 20%) to understand the codebase, your level of technical debt, and proposals from engineers, but coding can be a trap that keeps you from doing what you need to do to enable your team. In a worse case, technical managers can become micromanagers, and their opinions can have so much outsized influence that they lead to bad decisions.